Laminated resin formed body, method for producing laminated resin formed body, and multilayer article

ABSTRACT

It is an object of the present invention to provide a laminated resin molding which comprises a layer of a thermoplastic polymer such as a thermoplastic elastomer and a layer of a thermoplastic resin such as a fluorine-containing ethylenic polymer, is excellent in liquid chemical impermeability, chemical resistance and bacteria resistance, among others, and can be molded by coextrusion without causing foaming or deterioration of the thermoplastic elastomer and, further, has good interlaminar adhesive strength. The invention provides a laminated resin molding comprising a thermoplastic polymer layer (A), a polyamide-based resin layer (B) and a thermoplastic resin layer (C), wherein said thermoplastic polymer layer (A), said polyamide-based resin layer (B) and said thermoplastic resin layer (C) are laminated in that order and firmly adhered to one another, said thermoplastic polymer is to adhere to the polyamide-based resin by thermal fusion bonding, said polyamide-based resin has an amine value of 10 to 60 (equivalents/10 6  g), said thermoplastic resin contains a functional group and is to thereby firmly adhere to said polyamide-based resin by thermal fusion bonding, said functional group contains carbonyl group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation of application Ser. No. 10/560,910 filed Dec. 16,2005, which is a 371 of PCT Application No. PCT/JP2004/008452 filed Jun.16, 2004, the above-noted applications incorporated herein by referencein their entirety.

TECHNICAL FIELD

The present invention relates to a laminated resin molding and a methodof producing the same as well as a multilayer molded article comprisingthe laminated resin molding.

BACKGROUND ART

Fluororesins are excellent in such characteristics as chemicalresistance, nonstickiness, gas barrier properties, elution resistance,antifouling properties and bacteria resistance and, therefore, are usedfor the usage of liquid chemical-transport tubes, tubes for feedingcoatings, tubes for drinks and other tubes for industrial use. Since,however, they are expensive, laminated tubes comprising a fluororesinlayer and a layer of one of various thermoplastic resins which coversthe outer peripheral surface of the fluororesin layer have beenproposed.

Laminated resin moldings resulting from lamination of a polyamide resinlayer with a fluororesin layer are said to be suited for use asmultilayer molded articles required to have good mechanicalcharacteristics and low permeability for liquid chemicals, such assolvents and fuels, which cause deterioration of the polyamide resin,for example, automobile fuel piping tubes or hoses.

As regards multilayer tubes the outer layer of which is made of apolyamide resin, with the inner layer being made of a fluororesin, ithas been proposed that the tubes be irradiated to introduce crosslinkedstructures among molecules of both layers and thereby secure theadhesion between the polyamide resin layer and fluororesin layer (cf.e.g. Patent Document 1). For practicing this technology, however, it isindispensable to introduce expensive equipment and, in addition, theprocedural steps become complicated; this is a great problem from theproductivity viewpoint.

On the idea that fluororesins themselves should be improved to enablethe employment of the coextrusion technique excellent in productivity,various fluororesin materials have been proposed. As one of them, acarbonate and/or haloformyl group-containing, fluorine-containingethylenic polymer has been disclosed as a fluororesin for use inproducing laminates together with a polyamide resin (cf. e.g. PatentDocument 2).

However, for use as liquid chemical-transport tubes, tubes for feedingcoatings, tubes for drinks or other tubes for industrial use or certainfuel tubes, such resin laminates made of a polyamide resin layer and afluororesin layer are unsatisfactory in flexibility and, since thepolyamide resin is a crystalline resin, the problem of low transparencyis encountered in the fields of application where the visibility fromthe outside is required.

On the other hand, thermoplastic elastomers such as polyurethane-basedelastomers have characteristics similar to those of vulcanized rubbersand at the same time can be molded in the same manner as ordinarythermoplastic resins and, in addition, they are excellent in suchcharacteristics as flexibility and transparency; hence, they are used ina wide range of applications, typically in tubes for industrial use.However, there is a problem, namely thermoplastic elastomers areinferior in chemical resistance, chemical liquid impermeability, andbacteria resistance, among others.

To solve the problems with thermoplastic elastomers, resin laminateshave been proposed which comprise a layer of a fluororesin excellent inchemical resistance, liquid chemical impermeability and bacteriaresistance as well as in nonstickiness, elution resistance andantifouling properties, among others, and a layer of one of variousthermoplastic resins as laid on the outer surface of the fluororesinlayer.

Thus, a tube resulting from lamination by coextrusion usingpoly(vinylidene fluoride), for instance, as the fluororesin has beendisclosed as the laminate composed of a polyurethane-based elastomerlayer and a fluororesin layer (cf. e.g. Patent Document 3 and PatentDocument 4). However, the tube obtained is insufficient in interlaminarbonding between the polyurethane-based elastomer layer and fluororesinlayer, hence readily undergoes delamination upon repeated bending andvibration during use and, in addition, it has a problem in that it isinsufficient in liquid chemical impermeability and chemical resistance.

In cases where a thermoplastic elastomer layer and a fluororesin layerare subjected to lamination with a polyamide resin layer as anintermediate layer, the polyamide resin, when heated and melted in thestep of molding, generally tends to be decomposed with ease to generatelow-molecular-weight substances or to gelate. To avoid this andsimultaneously prevent the discoloration due to oxidation etc., amonocarboxylic acid or a derivative thereof is generally added in thestep of polymerization to effect the so-called terminal blocking.Therefore, the polyamide resins in wide use generally have an aminevalue of lower than 10 (equivalents/10⁶ g).

When the polyamide resin has an amine value of lower than 10(equivalents/10⁶ g), it is necessary to carry out the coextrusion withthe fluororesin at a high temperature of at least 260° C. to attain asufficient level of interlaminar adhesive strength between the polyamideresin layer and fluororesin layer. At such a high temperature, however,the thermoplastic elastomer causes troubles in the molding step, forexample foaming, so that the art has the problem that the polyamideresin and fluororesin cannot be coextruded.

As regards the resin laminate comprising a polyamide resin layer as theouter layer and a fluorine-containing ethylenic polymer layer as theinner layer, it is described in the art that a rubber layer may beprovided as the outermost layer (cf. e.g. Patent Document 5). Thisdescription, however, only gives a rubber layer as the layer usable asthe outermost layer, without giving any concrete description about therubber species, the laminating conditions or the effects of the rubberlayer provided, etc.

A resin laminate consisting of a fluorine-containing ethylenic polymerlayer, a polyamide resin layer and a thermoplastic elastomer layer aslaminated in that order has been disclosed (cf. e.g. Patent Document 6).This patent document, however, gives no description about such aspecific feature of the polyamide resin as the amine value thereof.

Thus, in the art, there is no technology available of coextruding athermoplastic elastomer, a polyamide resin and a fluororesin, and noresin laminates produced by lamination of a fluororesin with athermoplastic elastomer are excellent in interlaminar bonding, chemicalresistance or transparency.

There are further problems; when such resin laminates produced bylamination of a polyamide resin layer and a fluororesin layer are usedunder such severe conditions that each face of the laminates is incontact with a liquid chemical, the polyamide resin may be deterioratedas a result of penetration of the liquid chemical from the polyamideresin side, rendering the laminates no more fully durable in practicaluse, or the laminates may change markedly in size as a result ofswelling of the polyamide resin and/or elution of the additive(s)contained in the laminates. Further, the use of a fluororesin in theform of a single layer produces not only the expensiveness problemmentioned above but also the problem that the strength is insufficient,which is a weak point of the fluororesin.

When such resin laminates consisting of a polyamide resin layer and afluororesin layer laminated with each other are used as undergroundtubes in gas stations, in particular, they are generally used in theform of double tubes and, in that case, it is likely for the inner tubeto come into contact with a fuel both on the outer side and on the innerside, and the outer tube is of course buried in the ground. Therefore,both tubes are required to have low fuel permeability and sufficienttube strength for embodiment while retaining such characteristics aschemical resistance, nonstickiness, elution resistance, antifoulingproperties and bacteria resistance on both sides. However, there is noone available that satisfies all of such requirements.

Patent Document 1: Japanese Kokai Publication H05-8353 Patent Document2: International Laid-open Patent Application WO 99/45044 PatentDocument 3: Japanese Kokai Publication H08-142151 Patent Document 4:Japanese Kokai Publication H10-286897 Patent Document 5: InternationalLaid-open Patent Application WO 01/58686 Patent Document 6:International Laid-open Patent Application WO 98/58973 DISCLOSURE OFINVENTION Problems which the Invention is to Solve

In view of the above-discussed state of the art, it is an object of thepresent invention to provide a laminated resin molding which comprises alayer of a thermoplastic polymer such as a thermoplastic elastomer and alayer of a thermoplastic resin such as a fluorine-containing ethylenicpolymer, is excellent in liquid chemical impermeability, chemicalresistance and bacteria resistance, among others, and can be molded bycoextrusion without causing foaming or deterioration of thethermoplastic elastomer and, further, has good interlaminar adhesivestrength.

Another object, in addition to the above object, of the invention is to(1) provide the above-mentioned laminated resin molding with flexibility(hereinafter sometimes referred to as “first object of the invention”)or (2) provide the above-mentioned laminated resin molding withnonstickiness, elution resistance, antifouling properties and resinmolding-due strength to thereby provide a laminated resin moldingsufficiently durable in practical use while maintaining the abovecharacteristics even under severe conditions such that both faces of thelaminate are in contact with a liquid chemical, with the changes in sizeof the laminate due to resin deterioration or swelling or additiveelution being suppressed as far as possible (hereinafter sometimesreferred to as “second object of the invention”) by selecting thethermoplastic polymer species.

Means for Solving the Problems

This invention provides a laminated resin molding comprising athermoplastic polymer layer (A), a polyamide-based resin layer (B) and athermoplastic resin layer (C), wherein said thermoplastic polymer layer(A), said polyamide-based resin layer (B) and said thermoplastic resinlayer (C) are laminated in that order and firmly adhered to one another,said thermoplastic polymer is to adhere to the polyamide-based resin bythermal fusion bonding, said polyamide-based resin has an amine value of10 to 60 (equivalents/10⁶ g), said thermoplastic resin contains afunctional group and is to thereby firmly adhere to said polyamide-basedresin by thermal fusion bonding, said functional group contains carbonylgroup.

The invention provides, as the means for accomplishing the first objectof the invention, in particular, a method for producing the abovelaminated resin molding, which comprises laminating by the simultaneousmultilayer coextrusion technique using a coextruding machine comprisinga die and a plurality of extruders each for feeding a resin to said die,said die temperature being not higher than 250° C.

This invention further provides a multilayer molded article comprisingthe above laminated resin molding.

In the following, the present invention is described in detail.

The laminated resin molding of the invention comprises a thermoplasticpolymer layer (A), a polyamide-based resin layer (B) and a thermoplasticresin layer (C).

The thermoplastic polymer layer (A), the polyamide-based resin layer (B)and the thermoplastic resin layer (C) are laminated in that order.

The thermoplastic polymer forming the thermoplastic polymer layer (A) inthe laminated resin molding of the invention is to adhere to thepolyamide-based resin by thermal fusion bonding. The phrase “adhesion bythermal fusion bonding” means that when the laminated resin moldingaccording to the invention as produced by thermal fusion bonding istested, the initial adhesive strength between the thermoplastic polymerlayer (A) and the polyamide-based resin layer (B) is not lower than 25N/cm. The “adhesion by thermal fusion bonding” includes, within themeaning thereof, the case of impossibility of layer separation.

The initial adhesive strength is given herein in terms of the valueobtained by the initial adhesive strength measurement method describedlater herein.

The thermoplastic polymer is not particularly restricted but may be anyof those capable of being adhered to the polyamide-based resin bythermal fusion bonding. In achieving the first object of the invention,however, a flexible one is preferred; thus, that polymer preferably hasa 100% modulus value of not exceeding 35 MPa, more preferably notexceeding 20 MPa, as determined in accordance with JIS K 7311. Asufficient level of mechanical strength can be attained even if the 100%modulus value is not lower than 2 MPa, for instance, provided that it isnot higher than 35 MPa.

As the thermoplastic polymer, there may be mentioned, for example, athermoplastic resin and a thermoplastic elastomer. The thermoplasticresin includes polyolefin resins such as polyethylene and polypropylene;polyester resins such as polyethylene terephthalate [PET] andpolybutylene terephthalate [PBT]; polycarbonate resins; poly(vinylchloride) resins; fluororesins; and modified resins derived from theseand/or mixtures of two or more of these.

Unless otherwise specified, the term “thermoplastic polymer” as usedherein means the one forming the thermoplastic polymer layer (A)mentioned above. The thermoplastic polymer so referred to herein is theone forming the thermoplastic polymer layer (A) and conceptually differsfrom the polyamide-based resin forming the polyamide-based resin layer(B) and from the thermoplastic resin forming the thermoplastic resinlayer (C) in that it is not limited either to the one having an aminevalue within the range mentioned later herein or to the carbonylgroup-containing one described later herein. In the same manner as thethermoplastic polymer conceptually differs from the thermoplastic resinforming the thermoplastic resin layer (C), those thermoplastic resinsenumerated hereinabove as examples of the thermoplastic polymerconceptually differ from the thermoplastic resin forming thethermoplastic resin layer (C). In forming one laminated resin moldingbelonging to the laminated resin molding of the invention, theresin/polymer used as the above-mentioned thermoplastic polymer, thatused as the polyamide-based resin for forming the polyamide-based resinlayer (B) and that used as the thermoplastic resin for forming thethermoplastic resin layer (C) may be the same or different in kind fromone another, or the resin/polymer used as the thermoplastic polymer andthat used as the thermoplastic resin for forming the thermoplastic resinlayer (C) may be of the same kind.

The thermoplastic elastomer has rubber elasticity at ordinarytemperature and, at elevated temperatures, it is plasticated and can bemolded into desired shapes and forms. Preferably, the thermoplasticelastomer comprises at least one species selected from the groupconsisting of styrene/butadiene-based elastomers, polyolefin-basedelastomers, polyester-based elastomers, polyurethane-based elastomers,poly(vinyl chloride)-based elastomers, polyamide-based elastomers andfluorine-containing elastomers, since these elastomers are excellent inadhesion to the polyamide-based resin, which is to be described laterherein.

In accomplishing the first object of the invention, the thermoplasticpolymer is preferably a thermoplastic elastomer which makes it easy tosecure flexibility and transparency.

In accomplishing the first object of the invention, the thermoplasticelastomer preferably comprises at least one species selected from thegroup consisting of styrene/butadiene-based elastomers, polyolefin-basedelastomers, polyester-based elastomers, polyurethane-based elastomers,poly(vinyl chloride)-based elastomers, and polyamide-based elastomers.

As the styrene/butadiene-based elastomers [SBCs], there may bementioned, among others, styrene/butadiene/styrene copolymers,styrene/isoprene/styrene copolymers, andstyrene/ethylene/butadiene/styrene copolymers. As the polyolefin-basedelastomers [TPOs], there may be mentioned polypropylene/polyethyleneoxide/polypropylene copolymers and polypropylene/polyolefin-basednoncrystalline polymer/polypropylene copolymers, among others. As thepolyester-based elastomers [TPEEs], there may be mentioned, for example,polybutylene terephthalate/polyether/polybutylene terephthalatecopolymers. As the polyurethane-based elastomers [TPUs], there may bementioned, for example, ones produced by using a polyester polyol,polyether polyol or polycarbonate polyol as the long-chain diol. As thepoly(vinyl chloride)-based elastomers [TPVCs], there may be mentioned,for example, PVC/plasticizer and PVC/rubber blends resulting frompartial crosslinking of the PVC thereof. As the polyamide-basedelastomers [TPAEs], there may be mentioned nylon 6/polyester copolymers,nylon 6/polyether copolymers, nylon 12/polyester copolymers and nylon12/polyether copolymers, among others. As the fluorine-containingelastomers, there may be mentioned fluororesin/fluororubber blockcopolymers and so forth.

The thermoplastic elastomer may comprise one or more of those mentionedabove and may further be modified so that the adhesion to nylons may beimproved.

The thermoplastic elastomer is preferably a polyurethane-based elastomersince this is excellent in wear resistance and in adhesion to thepolyamide resin, which is to be described later herein.

The structure of the polyurethane-based elastomer may be any one thatcomprises a soft segment comprising polymeric glycol, a hard segmentcomprising a monomolecular chain extender and an isocyanate. Eachsegment that can be used in the above polyurethane-based elastomer has ahardness within the range of 65 to 100 as measured on a type A Shoredurometer according to ASTM D 2240. A preferred lower limit to theabove-mentioned hardness is 75, a more preferred lower limit is 80, apreferred upper limit is 95, and a more preferred upper limit is 90.

In another preferred embodiment, the thermoplastic elastomer is apolyolefin-based elastomer in view of the flexibility thereof, and onehaving a hardness within the range of 40 to 90 as measured using a typeA Shore durometer according to ASTM D 2240. A more preferred range is 45to 80.

In accomplishing the second object of the invention, the thermoplasticpolymer is preferably a fluororesin since this prevents the laminatefrom changing in size and makes it easy to attain chemical resistance,nonstickiness, elution resistance, antifouling properties and bacteriaresistance.

The fluororesin to be used as the thermoplastic polymer is conceptuallythe same as the resin comprising a fluorine-containing ethylenicpolymer, which is to be described later herein. In cases where afluororesin is used as the thermoplastic polymer and a resin comprisinga fluorine-containing ethylenic polymer is used as the thermoplasticresin forming the thermoplastic resin layer (C) to be described laterherein, the former fluororesin and the latter fluorine-containingethylenic polymer may be of the same kind or be different in kind in onelaminated resin molding.

In forming the thermoplastic polymer layer (A) in the practice of theinvention, the above-mentioned thermoplastic polymer may be usedtogether with at least one additive such as a plasticizer, impactmodifier, pigment, inorganic material, carbon black, acetylene black orlike electrically conductive material, and/or a resin and/or rubberother than the thermoplastic polymer. The additive and/or resin and/orrubber may be the same as or different from that used in thethermoplastic resin layer (C) and/or polyamide resin layer (A).

The polyamide-based resin, which forms the polyamide-based resin layer(B) in the laminated resin molding of the invention, comprisescrystalline polymers having the amide bond [—NHCO—] as a repeating unitwithin each molecule. As such polyamide-based resin, there may bementioned, for example, resins consisting of crystalline polymers inwhich the amide bond is bound to aliphatic structures or alicyclicstructures, namely the so-called nylon resins. As the nylon resins,there may be mentioned, for example, nylon 6, nylon 11, nylon 12, nylon610, nylon 612, nylon 6/66, nylon 66/12, and blends of at least two ofthese.

The polyamide-based resin may also be one containing a partial structurehaving no repeating unit amide bond as bound via block or graft bonding.As such polyamide-based resin, there may be mentioned, for example, onescomprising a polyamide resin elastomer such as a nylon 6/polyestercopolymer, nylon 6/polyether copolymer, nylon 12/polyester copolymer ornylon 12/polyether copolymer. These polyamide resin elastomers are blockcopolymers derived from nylon oligomers and polyester oligomers orpolyether oligomers via ester or ether bonding. As the polyesteroligomers, there may be mentioned, for example, polycaprolactone,polyethylene adipate and the like. As the polyether oligomers, there maybe mentioned, for example, polyethylene glycol, polypropylene glycol,and polytetramethylene glycol.

In cases where a thermoplastic elastomer having a low melting point isused as the thermoplastic polymer, the polyamide-based resin should becapable of being coextruded therewith at a relatively low temperature atwhich the thermoplastic elastomer will not produce any bubbles and,further, the polyamide-based resin layer formed should have a sufficientlevel of mechanical strength by itself even when it is a thin layer. Inthese respects, the polyamide-based resin preferably comprises at leastone species selected from the group consisting of nylon 6, nylon 11,nylon 12, nylon 610, nylon 612, nylon 6/66, nylon 66/12, nylon6/polyester copolymers, nylon 6/polyether copolymers, nylon 12/polyestercopolymers, nylon 12/polyether copolymers, and blends of two or more ofthese. Among these, nylon 11, nylon 12 and nylon 612 are more preferredin view of their good flexibility, in particular.

The polyamide-based resin has an amine value of 10 to 60(equivalents/10⁶ g). When, in the practice of the invention, the aminevalue of the polyamide-based resin is selected within the above range,the interlaminar adhesive strength between polyamide-based resin layer(B) and thermoplastic resin layer (C) can be increased even in the caseof using, for example, a thermoplastic elastomer as the thermoplasticpolymer and carrying out coextrusion at a relatively low temperaturesuch that the thermoplastic elastomer will not foam. When the aminevalue is lower than 10 (equivalents/10⁶ g), the interlaminar adhesivestrength between the polyamide-based resin layer (B) and thermoplasticresin layer (C) will become insufficient on the occasion of coextrusionat a relatively low temperature at which the thermoplastic elastomerwill not foam. When it exceeds 60 (equivalents/10⁶ g), the laminatedresin molding obtained will be unsatisfactory in mechanical strengthand, further, tends to discolor during storage, and the handleabilitywill become poor. A preferred lower limit is 15 (equivalents/10⁶ g),while a preferred upper limit is 50 (equivalents/10⁶ g) and a morepreferred upper limit is 35 (equivalents/10⁶ g).

The amine value so referred to herein is the value obtained by the aminevalue measurement method described later herein and, unless otherwisespecified, means the amine value of the polyamide-based resin prior tolamination. Among the number of amino groups which the polyamide-basedresin before lamination has, some are presumably consumed in adhering tothe thermoplastic resin layer (C). Since, however, the number thereof isvery small as compared with the whole polyamide-based resin layer (B),the amine value of the polyamide-based resin before lamination and theamine value of the resin in the polyamide-based resin layer (B) aresubstantially of the same order.

The polyamide-based resin to be used in the practice of the inventionpreferably has an acid value of not higher than 80 (equivalents/10⁶ g).Even if the acid value is higher than 80 (equivalents/10⁶ g), theinterlaminar adhesive strength between the polyamide-based resin layer(B) and thermoplastic resin layer (C) as attained by using athermoplastic elastomer, for instance, as the thermoplastic polymer andcarrying out coextrusion at a relatively low temperature such that thethermoplastic elastomer will not foam will be satisfactory so long asthe amine value is within the above range. Generally, however, themolecular weight of a polyamide-based resin fairly depends on the aminevalue and acid value desired or specified and, in this respect, an acidvalue exceeding 80 (equivalents/10⁶ g), which may possibly lead to areduction in the molecular weight of the polyamide-based resin, isundesirable. The acid value is more preferably not higher than 70(equivalents/10⁶ g), still more preferably not higher than 60(equivalents/10⁶ g). The acid value so referred to herein is the valueobtained by the acid value measurement value described later herein.

In the practice of the invention, the melting point of thepolyamide-based resin is not particularly restricted but preferably hasa melting point of not lower than 130° C. When the melting point islower than 130° C., the polyamide-based resin layer (B) formed may bepoor in mechanical characteristics and/or heat resistance, among others,in certain instances. The preferred upper limit may appropriately beselected according to the heat resistance of the thermoplastic polymerforming the thermoplastic polymer layer (A). A preferred upper limit is260° C., a more preferred upper limit is 230° C., a still more preferredupper limit is 210° C., and a more preferred lower limit is 150° C. Themelting point so referred to herein is given in terms of the valuemeasured on a differential scanning calorimeter [DSC].

When, in the practice of the invention, the polyamide-based resin isused in extrusion molding or blow molding, for instance, the molecularweight thereof as expressed in terms of relative viscosity is preferablynot lower than 1.8. If it is lower than 1.8, the moldability in suchmolding as mentioned above will be inferior and the mechanical strengthof the laminated resin molding may decrease in certain instances. Morepreferably, it is not lower than 2.0. On the other hand, the upper limitis preferably set at 4.0. When it exceeds 4.0, it is difficult to obtainthe polyamide-based resin itself by polymerization and, in certaininstances, reduced moldability on the occasion of molding thereof mayresult. The relative viscosity is measured in accordance with JIS K6810.

In forming the polyamide-based resin layer (B), the polyamide-basedresin may also be used together with a plasticizer and/or some resinother than the polyamide-based resin in such an amount as not to becontrary to the object of the invention. The plasticizer can improve theflexibility of the polyamide-based resin layer (B) formed and, inparticular, can improve the low-temperature mechanical characteristicsof the laminated resin molding.

The plasticizer is not particularly restricted but includes, amongothers, hexylene glycol, glycerol, β-naphthol, dibenzylphenol,octylcresol, bisphenol A, octyl p-hydroxybenzoate, 2-ethylhexylp-hydroxybenzoate, heptyl p-hydroxybenzoate, p-hydroxybenzoicacid-ethylene oxide and/or propylene oxide adducts, octylp-hydroxybenzoate, 2-ethylhexyl p-hydroxybenzoate, heptylp-hydroxybenzoate, E-caprolactone, phosphate esters of phenols,N-methylbenzenesulfonamide, N-ethylbenzenesulfonamide,N-butylbenzenesulfonamide, toluenesulfonamide,N-ethyltoluenesulfonamide, and N-cyclohexyltoluenesulfonamide.

The shock resistance of the laminated resin molding can be improved byusing the polyamide-based resin together with some resin other than thepolyamide-based resin to form the polyamide-based resin layer (B).Preferred as the other resin to be used together with thepolyamide-based resin to form the polyamide-based resin layer (B) arethose having good compatibility with the polyamide-based resin,including, among others, ester- and/or carboxylic acid-modified-olefinresins; acrylic resins, in particular glutarimide group-containingacrylic resins; ionomer resins; polyester resins; phenoxy resins;ethylene/propylene/diene copolymers; and polyphenylene oxide. As theester- and/or carboxylic acid-modified olefin resins, there may bementioned, for example, ethylene/methyl acrylate copolymers,ethylene/acrylate copolymers, ethylene/methyl acrylate/maleic anhydridecopolymers, ethylene/ethyl acrylate copolymers, and propylene/maleicanhydride copolymers.

The polyamide-based resin layer (B) can also be formed by using thepolyamide-based resin together with a colorant and/or one or more ofvarious additives each used in such an amount as not to be contrary tothe object of the invention. As the additives, there may be mentioned,for example, antistatic agents, flame retardants, heat stabilizers,ultraviolet absorbers, lubricants, mold release agents, nucleatingagents, and reinforcing agents (fillers).

The thermoplastic resin to form the thermoplastic resin layer (C) in thelaminated resin molding of the invention may be any of those generallyrecognized as thermoplastic resins. Preferably, however, thethermoplastic resin comprises a fluorine-containing ethylenic polymer.Unless otherwise specified, the term “thermoplastic resin” as usedhereinafter means that one used for forming the thermoplastic resinlayer (C), which may be the same or different in kind as or from thethermoplastic polymer forming the thermoplastic polymer layer (A) but isdifferent from the polyamide-based resin forming the polyamide-basedresin layer (B).

The above-mentioned thermoplastic resin contains a functional group andis to thereby firmly adhere to the polyamide-based resin forming thepolyamide-based resin layer (B) by thermal fusion bonding. Without anyfunctional group, the interlaminar adhesive strength will be so low thatdelamination may occur during use; this is a problem from the practicalviewpoint. The phrase “to firmly adhere” as used above means that theinitial adhesive strength between the polyamide-based resin layer (B)and thermoplastic resin layer (C) in the laminated resin molding of theinvention as laminated by thermal fusion bonding is not lower than 25N/cm. When it is lower than 25 N/cm, delamination may occur between thepolyamide-based resin layer (B) and thermoplastic resin layer (C). Theinitial adhesive strength between the polyamide-based resin layer (B)and thermoplastic resin layer (C) may be not higher than 60 N/cm, forinstance, provided that it is not lower than 25 N/cm.

Therefore, the above-mentioned thermoplastic resin is required to be afunctional group-containing one so that firm adhering thereof to thepolyamide-based resin layer (B) may be established by thermal fusionbonding. This functional group may be any one that can be involved inthe adhering to the polyamide-based resin forming the polyamide-basedresin layer (B). The group capable of being involved in the adhering tothe polyamide-based resin forming the polyamide-based resin layer (B) ishereinafter referred to as “adhesive functional group”. In the practiceof the invention, the thermoplastic resin is an adhesive functionalgroup-containing one. The adhesive functional group so referred toherein is practically a group capable of coordinating or reacting with agroup, such as an amide bond or amino group, which the crystallinepolymer constituting the polyamide-based resin and includes, within themeaning thereof, not only those groups which are generally referred toas functional groups but also those groups which are generally referredto as bonds, such as ester bonds, on condition that they have suchcoordinating or reacting ability as mentioned above. The groupsgenerally referred to as bonds are present on side chains or in the mainchain of the polymer in the thermoplastic resin.

By saying that “the thermoplastic resin is an adhesive functionalgroup-containing one”, it is meant that while the thermoplastic resingenerally comprises a polymer, the polymer is an adhesive functionalgroup-containing one.

The number of the adhesive functional groups which the thermoplasticresin has can be appropriately selected according to counterpartmaterial for lamination, shape and form, purpose of adhesion, intendeduse, required adhesive strength, thermoplastic resin species anddifferences in method of adhesion, among others. Preferably, the numberof adhesive functional groups is 3 to 1000 per 1×10⁶ main chain carbonatoms of the polymer in the thermoplastic resin. When it is less than 3,the interlaminar adhesive strength between polyamide-based resin layer(B) and thermoplastic resin layer (C) may be insufficient in certaininstances. When it exceeds 1000, a gas generated as a result of achemical change of the adhesive functional group on the occasion ofadhesion and entering the adhesion interface adversely affects theadhesion, reducing the interlaminar adhesive strength between thepolyamide-based resin layer (B) and thermoplastic resin layer (C) incertain instances. As for the number of adhesive functional groups, amore preferred lower limit thereto is 10, a more preferred upper limitis 500, and a still more preferred upper limit is 300, per 1×10⁶ mainchain carbon atoms in the polymer in the thermoplastic resin. The numberof functional groups so referred to herein is the value obtained byinfrared spectral analysis as mentioned later herein and, unlessotherwise specified, it means the number of functional groups which thepolymer in the thermoplastic resin before lamination has.

As the adhesive functional group, there may be mentioned, for example,groups containing a carbonyl group. The carbonyl group-containinggroups, there may be mentioned carbonyl, carbonate, haloformyl, formyl,carboxyl, ester, acid anhydride [—C(═O)O—C(═O)—], and isocyanato groupsor bonds, among others. On the contrary, amide [—C(═O)—NH—], imide[—C(═O)—NH—C(═O)—], urethane [—NH—C(═O)O—], urea [—NH—C(═O)—NH—] andlike groups or bonds, which also contain [—C(═O)—], unlike such onesenumerated hereinabove as carbonyl and carbonate groups, are poor inreactivity and, essentially, are incapable of reacting with the group orgroups in the crystalline polymer constituting the polyamide-basedresin, which forms the polyamide-based resin layer (B). Therefore, asfar as the present invention is concerned, at least the amide, imide,urethane or urea group or bond is not included under the category ofcarbonyl group-containing groups. Preferred as the carbonylgroup-containing group are carbonate groups and haloformyl groups,because of the ease of introduction thereof and the high reactivitythereof with the group or groups which the crystalline polymerconstituting the polyamide-based resin has.

The carbonate groups are groups comprising the bond generallyrepresented by —OC(═O)O— and are represented by —OC(═O)O—R (in which Rrepresents an organic group or a group VII atom, wherein the organicgroup is, for example, a C₁ to C₂₀ alkyl group, on particular a C₁ toC₁₀ alkyl group, or an ether bond-containing C₂ to C₂₀ alkyl group). Aspreferred examples of the carbonate group, there may be mentioned, forexample, —OC(═O)OCH₃, —OC(═O)OC₃H₇, —OC(═O)OC₈H₁₇ and—OC(═O)OCH₂CH₂CH₂OCH₂CH₃.

The haloformyl groups are represented by —COY (in which Y represents agroup VII atom) and include —COF and —COCl, among others.

The thermoplastic resin to be used in the practice of the invention isan adhesive functional group-containing one, and each adhesivefunctional group may be bound either to a terminus of the polymer in thethermoplastic resin or to a side chain. When the adhesive functionalgroup is a carbonyl group-containing group and the carbonyl group-is apart of a carbonate group and/or haloformyl group, the thermoplasticresin includes:

(1) thermoplastic resins containing the carbonate group alone at aterminus or termini or on at least one side chain;(2) thermoplastic resins containing the haloformyl group alone at aterminus or termini or on at least one side chain; and(3) thermoplastic resins containing both the carbonate group andhaloformyl group each at a terminus or termini or on at least one sidechain, and may be any one of these. Among them, those having an adhesivefunctional group at a terminus or termini are preferred because theywill not markedly reduce the heat resistance, mechanical characteristicsor chemical resistance and because they are advantageous from theproductivity and cost viewpoint.

In the thermoplastic resin mentioned above, there may be present someadhesive functional group-free polymer molecules on condition that otherpolymer molecules present therein are molecules containing such anadhesive functional group or groups as mentioned above.

The specific species to be used as the thermoplastic resin mentionedabove is to be appropriately selected according to the purpose, use,method of use, the resin species forming the thermoplastic polymer layer(A) and polyamide-based resin layer (B). Preferably, the thermoplasticresin has a melting point of 160 to 240° C. When the melting point ofthe thermoplastic resin is within this range, good adhesion is attainedbetween the adhesive functional group(s) and the group(s) which thecrystalline polymer in the polyamide-based resin forming thepolyamide-based resin layer (B) contains, the moldability is good and,further, the transparency of the thermoplastic resin layer (C) isfavorably improved by carrying out coextrusion at a temperature adaptedto the melting point of the thermoplastic resin and lying within therange mentioned above. A preferred upper limit is 220° C.

The polymer in the thermoplastic resin is not particularly restrictedbut is preferable a fluorine-containing ethylenic polymer. Thefluorine-containing ethylenic polymer has those excellentcharacteristics intrinsic in fluororesins, for example chemicalresistance, solvent resistance, weather resistance, antifoulingproperties, nonstickiness and bacteria resistance, and can provide thelaminated resin molding obtained with such excellent characteristics.The fluorine-containing ethylenic polymer is the product ofpolymerization of at least one fluorine-containing ethylenic monomer. Itmay be the product of polymerization of a fluorine-containing ethylenicmonomer and a fluorine-free ethylenic monomer. The fluorine-containingethylenic monomer and fluorine-free ethylenic monomer each may compriseone single or two or more species.

The fluorine-containing ethylenic monomer is an olefinic unsaturatedmonomer containing one or more fluorine atoms but having no adhesivefunctional group and includes, among others, tetrafluoroethylene,vinylidene fluoride, chlorotrifluoroethylene, vinyl fluoride,hexafluoropropylene, hexafluoroisobutene, monomers represented by thegeneral formula (1):

CH₂═CX¹(CF₂)_(n)X²  (1)

wherein X¹ represents H or F, X² represents H, F or Cl and n representsan integer of 1 to 10, and perfluoro(alkyl vinyl ether) species.

The fluorine-free ethylenic monomer mentioned above is an olefinicunsaturated monomer containing neither fluorine atom nor adhesivefunctional group and, from the viewpoint of no risk of weakening theheat resistance or chemical resistance of the productfluorine-containing ethylenic polymer, among others, preferably is anethylenic monomer containing not more than 5 carbon atoms, for exampleethylene, propylene, 1-butene, 2-butene, vinyl chloride or vinylidenechloride.

In preparing the fluorine-containing ethylenic polymer by polymerizationof a fluorine-containing ethylenic monomer and a fluorine-free ethylenicmonomer, the monomer composition may be such that thefluorine-containing ethylenic monomer amounts to 10 to 100 mole percentand the fluorine-free ethylenic monomer to 0 to 90 mole percent. Apreferred lower limit to the proportion of the fluorine-containingethylenic monomer is 30 mole percent, and a preferred upper limit to theproportion of the fluorine-containing ethylenic monomer is 70 molepercent. When the fluorine-containing ethylenic monomer proportion issmaller than 10 mole percent, the resulting fluorine-containingethylenic polymer will fail to acquire the fluororesin-specificcharacteristics and, therefore, such a proportion is undesirable.

The monomer composition expressed herein in terms of “mole percent”indicates the proportions, in the polymer, of the respective monomersadded and is expressed in terms of the mole fractions of the respectivemonomers added to form the polymer.

By selecting the fluorine-containing ethylenic monomer and fluorine-freeethylenic monomer species and the combination and proportions thereof,it is possible to adjust the melting point or glass transition point ofthe product fluorine-containing ethylenic polymer, and thefluorine-containing ethylenic polymer can be obtained either in a resinform or in an elastomer form. The properties of the fluorine-containingethylenic polymer can be adequately selected according to the object anduse of the adhesion and the purpose and use of the product laminatedresin molding.

The fluorine-containing ethylenic polymer preferably has a molecularweight within the range within which the fluorine-containing ethylenicpolymer can be molded at a temperature below the thermal decompositiontemperature thereof and, in addition, the laminated resin moldingobtained can manifest those good mechanical characteristics, chemicalresistance and other properties intrinsic in the fluorine-containingethylenic polymer. When the melt flow rate [MFR] is employed as amolecular weight index, the MFR at a temperature within the range ofabout 230 to 350° C., which is the molding temperature range for commonfluororesins, is preferably 0.5 to 100 g/10 minutes. More preferably,the MFR at a temperature of 265° C. is 1 to 50 g/10 minutes. The MFR soreferred to herein is the value obtained by the MFR measurement methodto be described later herein.

The fluorine-containing ethylenic polymer to be used in the practice ofthe invention is preferably one excellent in transparency, mostpreferably one showing, in the form of a 500-μm-thick film, a totalluminous transmittance of at least 85%.

Preferred as the fluorine-containing ethylenic polymer to be used in thepractice of the invention are tetrafluoroethylene unit-based,fluorine-containing ethylenic polymers in view of their good heatresistance and chemical resistance as well as vinylidene fluorideunit-based, fluorine-containing ethylenic polymers in view of their goodmoldability. The term “unit” as used herein denotes that moiety derivedfrom each monomer molecule which is a part of the molecular structure ofthe polymer.

When the polymer in the thermoplastic resin is a fluorine-containingethylenic polymer, the adhesive functional group may be found at aterminus or termini or on a side chain(s) of the fluorine-containingethylenic polymer. When the adhesive functional group is bound to apolymer terminus or termini, the fluorine-containing ethylenic polymercan be obtained, for example, by the method comprising using such apolymerization initiator as a peroxide, which will be described laterherein, and, when the adhesive functional group is bound to a sidechain(s), it can be obtained by copolymerizing an adhesive functionalgroup-containing ethylenic monomer and the above-mentionedfluorine-containing ethylenic monomer and/or fluorine-free ethylenicmonomer, as will be described later herein. The “adhesive functionalgroup-containing ethylenic monomer” is an olefinically unsaturatedmonomer having an adhesive functional group. The adhesive functionalgroup-containing ethylenic monomer may contain a fluorine atom(s) or befluorine-free but does not conceptually include either of the“fluorine-containing ethylenic monomer” and “fluorine-free ethylenicmonomer” mentioned above.

As some preferred specific examples of the fluorine-containing ethylenicpolymer to be used in the practice of the invention, there may bementioned those fluorine-containing ethylenic polymers (I)-(V) which arethe fluorine-containing ethylenic polymers obtained by polymerizing themonomer(s) specified below and are excellent in heat resistance,chemical resistance, weather resistance, electrical insulating qualityand nonstickiness. The monomer composition of each fluorine-containingethylenic polymer as reported herein is given in terms of values withthe sum of monomers other than the adhesive functional group-containingethylenic monomer as copolymerized in obtaining the fluorine-containingethylenic polymer having an adhesive functional group(s) on a sidechain(s) being taken as 100 mole percent.

(I) Copolymers obtained by polymerizing tetrafluoroethylene andethylene;(II) Copolymers obtained by polymerizing at least tetrafluoroethyleneand a compound represented by the general formula (ii):

CF₂═CF—Rf¹  (ii)

wherein Rf¹ represents CF₃ or ORf² (in which Rf² represents aperfluoroalkyl group containing 1 to 5 carbon atoms);(III) Polymers obtained by polymerizing at least vinylidene fluoride;(IV) Copolymers derived from at least the following a, b and c:a. 20 to 89 mole percent (a preferred upper limit being 70 mole percent)of tetrafluoroethylene,b. 10 to 79 mole percent (a preferred lower limit being 20 mole percentand a preferred upper limit being 60 mole percent) of ethylene, andc. 1 to 70 mole percent (a preferred upper limit being 60 mole percent)of a compound represented by the general formula (ii):

CF₂═CF—Rf¹  (ii)

wherein Rf¹ represents CF₃ or ORf² (in which Rf² represents aperfluoroalkyl group containing 1 to 5 carbon atoms); and(V) Copolymers derived from at least the following d, e and f:d. 15 to 60 mole percent of vinylidene fluoride,e. 35 to 80 mole percent of tetrafluoroethylene, andf. 5 to 30 mole percent of hexafluoropropylene.

Among them, the copolymers (IV) are preferred as the fluorine-containingethylenic polymer since they can give laminated resin moldings excellentin transparency.

As the copolymers (I), there may specifically be mentioned, amongothers, copolymers constituted at least of 20 to 89 mole percent oftetrafluoroethylene, 10 to 79 mole percent of ethylene and 0 to 70 molepercent of a monomer copolymerizable with these. A preferred upper limitto the tetrafluoroethylene content is 60 mole percent, and a preferredupper limit to the ethylene content is 60 mole percent and a preferredlower limit thereto is 20 mole percent.

As the monomer copolymerizable with tetrafluoroethylene and ethylene,there may be mentioned hexafluoropropylene, chlorotrifluoroethylene,monomers represented by the general formula (1) given above,perfluoro(alkyl vinyl ether) species, and propylene, among others.Generally, one or two or more of these are used.

Such fluorine-containing ethylenic polymers as the copolymers (I)mentioned above are especially excellent in heat resistance, chemicalresistance, weather resistance, electrical insulating quality,nonstickiness, gas barrier properties, elution resistance, and bacteriaresistance.

Among the copolymers (I) mentioned above, the following, among others,are preferred since they retain those excellent performancecharacteristics of tetrafluoroethylene/ethylene copolymers, theirmelting point can be reduced to a relatively low level and the adhesionproperties thereof can be made the most of against the counterpartmaterial in lamination:

(I-1) Copolymers derived at least from 62 to 80 mole percent oftetrafluoroethylene, 20 to 38 mole percent of ethylene and 0 to 10 molepercent of a monomer copolymerizable with tetrafluoroethylene andethylene; and(I-2) Copolymers derived at least from 20 to 80 mole percent oftetrafluoroethylene, 10 to 80 mole percent of ethylene, 0 to 30 molepercent of hexafluoropropylene and 0 to 10 mole percent of a monomercopolymerizable with tetrafluoroethylene and ethylene.

Preferred as the copolymers (II) are, for example, the following:

(II-1) Copolymers derived at least from 65 to 95 mole percent oftetrafluoroethylene and 5 to 35 mole percent of hexafluoropropylene;preferably, copolymers derived from at least 75 mole percent oftetrafluoroethylene and at most 25 mole percent of hexafluoropropylene;(II-2) Copolymers derived at least from 70 to 97 mole percent oftetrafluoroethylene and 3 to 30 mole percent of a monomer represented byCF₂═CFORf² (in which Rf² represents a perfluoroalkyl group containing 1to 5 carbon atoms); and(II-3) Copolymers resulting from polymerization of at leasttetrafluoroethylene, hexafluoropropylene and a monomer represented byCF₂═CFORf² (in which Rf² is as defined above), with the sum ofhexafluoropropylene and the monomer represented by CF₂═CFORf² being 5 to30 mole percent.

The copolymers (II-2) and (II-3) mentioned above are perfluoro-basedcopolymers and are particularly excellent in heat resistance, chemicalresistance, water repellency, nonstickiness, electrical insulatingquality, barrier properties, elution resistance and bacteria resistance,among others.

As the copolymers (III), there may be mentioned, among others,copolymers derived at least from 15 to 99 mole percent of vinylidenefluoride, 0 to 80 mole percent of tetrafluoroethylene and 0 to 30 molepercent of at least one of hexafluoropropylene andchlorotrifluoroethylene.

Thus, there may be mentioned, among others, the following:

(III-1) Copolymers derived at least from 30 to 99 mole percent ofvinylidene fluoride and 1 to 70 mole percent of tetrafluoroethylene;(III-2) Copolymers derived at least from 60 to 90 mole percent ofvinylidene fluoride, 0 to 30 mole percent of tetrafluoroethylene and 1to 20 mole percent of chlorotrifluoroethylene;(III-3) Copolymers derived at least from 60 to 95 mole percent ofvinylidene fluoride, 0 to 30 mole percent of tetrafluoroethylene and 5to 30 mole percent of hexafluoropropylene; and(III-4) Copolymers derived at least 15 to 60 mole percent of vinylidenefluoride, 35 to 80 mole percent of tetrafluoroethylene and 5 to 30 molepercent of hexafluoropropylene.

The method of producing the fluorine-containing ethylenic polymer to beused in the practice of the invention is not particularly restricted.When a fluorine-containing ethylenic polymer having adhesive functionalgroups on side chains, as mentioned above, is to be produced, thedesired polymer can be obtained by copolymerizing an adhesive functionalgroup-containing ethylenic monomer with one or more fluorine-containingethylenic monomer and a fluorine-free ethylenic monomer each adapted inkind and in proportion for the production of the desiredfluorine-containing ethylenic polymer. When the adhesive functionalgroup is a carbonyl group-containing group, preferred adhesive functiongroup-containing ethylenic monomers are perfluoroacryloyl fluoride,1-fluoroacryloyl fluoride, acryloyl fluoride, 1-trifluoromethacryloylfluoride, perfluorobutenoic acid or like fluorine-containing monomers;and acrylic acid, methacrylic acid, acryloyl chloride, vinylenecarbonate and like fluorine-free monomers.

For obtaining fluorine-containing ethylenic polymers having an adhesivefunctional group at one or each terminus of the polymer, various methodscan be employed. When the adhesive functional group is a carbonylgroup-containing group, the method comprising polymerizing the monomeror monomers which are to constitute the fluorine-containing ethylenicpolymer, using a peroxide, in particular a peroxycarbonate or peroxyester, as the polymerization initiator can be preferably employed fromthe economical viewpoint and from the viewpoint of such quality featuresas heat resistance and chemical resistance. By this method, it ispossible to introduce a peroxide-derived carbonyl group, for example aperoxycarbonate-derived carbonate group or a peroxy ester-derived estergroup, or a group derived from such a functional group by conversionthereof, for example a haloformyl group, into a polymer terminus. Amongsuch polymerization initiators, a peroxycarbonate is preferably usedsince the polymerization temperature can be lowered and the initiationreaction will not be accompanied by any side reaction.

Preferred as the peroxycarbonate are compounds represented by one of thegeneral formulas (1) to (4):

In the above formulas, R and R¹ are the same or different and eachrepresent a straight or branched univalent saturated hydrocarbon groupcontaining 1 to 15 carbon atoms or a straight or branched, alkoxylgroup-terminated, univalent saturated hydrocarbon group containing 1 to15 carbon atoms, and R² represents a straight or branched bivalentsaturated hydrocarbon group containing 1 to 15 carbon atoms or astraight or branched, alkoxyl group-terminated, bivalent saturatedhydrocarbon group containing 1 to 15 carbon atoms.

Preferred as the peroxycarbonate are, among others, diisopropylperoxycarbonate, di-n-propyl peroxydicarbonate, tert-butylperoxyisopropyl carbonate, bis(4-tert-butylcyclohexyl)peroxydicarbonate, and di-2-p-ethylhexyl peroxydicarbonate.

The dosage of the polymerization initiator such as a peroxycarbonate orperoxy ester may vary depending on the species, composition andmolecular weight of the desired fluorine-containing ethylenic polymer,the polymerization conditions and the initiator species employed, amongothers. Preferably, however, the initiator is used in an amount of 0.05to 20 parts by mass per 100 parts by mass of the fluorine-containingethylenic polymer to be obtained. A more preferred lower limit is 0.1part by mass, and a more preferred upper limit is 10 parts by mass.

The method of polymerization is not particularly restricted butincludes, for example, solution polymerization, suspensionpolymerization, emulsion polymerization and bulk polymerization.Preferred from the industrial viewpoint is the suspension polymerizationin an aqueous medium in which a fluorine-containing solvent is used anda peroxycarbonate or the like is used as the polymerization initiator.In the suspension polymerization, a fluorine-containing solvent can beused in admixture with water. As the fluorine-containing solvent to beused in the suspension polymerization, there may be mentionedhydrochlorofluoroalkanes such as CH₃CClF₂, CH₃CCl₂F, CF₃CF₂CCl₂H andCF₂ClCF₂CFHCl; chlorofluoroalkanes such as CF₂ClCFClCF₂CF₃ andCF₃CFClCFClCF₃; and perfluoroalkanes such as perfluorocyclobutane,CF₃CF₂CF₂CF₃, CF₃CF₂CF₂CF₂CF₃ and CF₃CF₂CF₂CF₂CF₂CF₃, for instance.Among them, perfluoroalkanes are preferred. The fluorine-containingsolvent is preferably used in an amount of 10 to 100% by mass relativeto water from the viewpoint of suspensibility and economy.

The polymerization temperature is not particularly restricted but may bewithin the range of 0 to 100° C. The polymerization pressure is to beadequately selected depending on the solvent species employed, theamount and vapor pressure thereof, the polymerization temperature andother polymerization conditions and, generally, it may be within therange of 0 to 9.8 MPaG.

For molecular weight adjustment, a conventional chain transfer agent,for example, a hydrocarbon such as isopentane, n-pentane, n-hexane orcyclohexane; an alcohol such as methanol or ethanol; or a halogenatedhydrocarbon such as carbon tetrachloride, chloroform, methylene chlorideor methyl chloride, can be used. The terminal carbonate or ester groupcontent can be controlled by modifying the polymerization conditionssuch as the peroxycarbonate or peroxy ester dosage, chain transfer agentdosage and polymerization temperature.

Various methods can be employed for obtaining haloformylgroup-terminated fluorine-containing ethylenic polymers. For example,they can be obtained by heating the carbonate or ester group-terminatedfluorine-containing ethylenic polymer mentioned above to effect thermaldegradation (decarboxylation). The heating temperature varies dependingon the carbonate or ester group species and the fluorine-containingethylenic polymer species, among others. It is desirable that thepolymer itself be heated to a temperature of 270° C. or above,preferably 280° C. or above, more preferably 300° C. or above but lowerthan the thermal decomposition temperature of the moieties of thefluorine-containing ethylenic polymer other than the carbonate or estergroups, hence, more preferably to 400° C. or below, still morepreferably 350° C. or below.

The thermoplastic resin layer (C) is preferably one formed by meltextrusion of the thermoplastic resin, more preferably one formed by meltextrusion of the above-mentioned fluorine-containing ethylenic polymer.As described above, the haloformyl group may be degraded to a carboxylgroup upon heating in the process of melt extrusion of thefluorine-containing ethylenic polymer, for instance, or with the lapseof time and, therefore, the carbonyl group content in the thermoplasticresin layer (C) is preferably 3 to 1000 groups per 1×10⁶ main chaincarbon atoms in the fluorine-containing ethylenic polymer and thecarbonyl group may be a part of the carbonate group, a part of thehaloformyl group and/or a part of the carboxyl group.

The thermoplastic resin layer (C) in the laminate of the invention maycontain one or more other components or ingredients incorporatedtherein, if necessary. Preferably, the layer is made of theabove-mentioned fluorine-containing ethylenic polymer and one or moreother components/ingredients incorporated in that polymer according toneed. While the fluorine-containing ethylenic polymer is preferably usedsingly so long as the adhesiveness, heat resistance, chemical resistanceand other characteristics of the polymer itself will not be impaired,the thermoplastic resin layer (C) can also be formed using that polymertogether with one or more of arbitrary additives, for example variousfillers such as inorganic powders, glass fibers, carbon fibers, metaloxides and carbon species, pigments, and ultraviolet absorbers, withinlimits within which the performance characteristics thereof as requiredfor the destination and intended use thereof will not be adverselyaffected. For the purpose of improving the mechanical characteristics,improving the weather resistance, providing an artistic design, reducingstatic electrical charges or improving the moldability, it is alsopossible to further use, with or without the additives, fluororesinsother than the resins comprising the above-mentioned fluorine-containingethylenic polymers, thermoplastic resins other than the polyamide-basedresins for forming the polyamide-based resin layer (B) and other thanthe resins comprising the fluorine-containing ethylenic polymers,thermosetting resins, synthetic rubbers, etc. The combined use of anelectrically conductive material such as carbon black or acetylene blackis advantageously effective in preventing static electricity fromaccumulating when the laminated resin molding obtained is used as a fuelpiping tube or a fuel piping hose.

The thermoplastic resin layer (C) may be an electrically conductive oneaccording to need. The term “electrically conductive” is used herein tomean that while continuous contacting of an inflammable fluid such asgasoline with an electrical insulator such as a resin may result instatic electricity accumulation, hence possibly in inflammation, theresin layer has electrical characteristics such that such staticelectricity accumulation can be prevented. According to the definitionin the standard SAEJ 2260, for instance, electrical conductivitycorresponds to a surface resistance of not higher than 10⁶Ω/□. The levelof addition of the electrically conductive material in rendering thethermoplastic resin layer (C) electrically conductive is preferably nothigher than 20% by mass, more preferably not higher than 15% by mass,relative to the sum of the resin(s) and optionalcomponent(s)/ingredient(s) forming the thermoplastic resin layer (C).The lower limit may be at such a level that the layer (C) can beprovided with the above-mentioned surface resistance.

As described hereinabove, the polyamide-based resin layer (B) in thelaminated resin molding of the invention is formed out of apolyamide-based resin having an amine value within the specified rangeand the thermoplastic resin layer (C) is formed out of an adhesivefunction group-containing, preferably carbonyl group-containing,thermoplastic resin and, therefore, the polyamide-based resin layer (B)and the thermoplastic resin layer (C) are firmly adhered together bythermal fusion bonding. The amide bonds in the polyamide-based resinforming the polyamide-based resin layer (B) and the adhesive functionalgroups in the thermoplastic resin forming the thermoplastic resin layer(C), upon heating, react with each other or interact with each other inthe manner of coordination, for instance, whereby the firm adhesionbetween the polyamide-based resin layer (B) and the thermoplastic resinlayer (C) can be obtained.

Further, as described hereinabove, the thermoplastic resin layer (C) inthe laminated resin molding of the invention is formed out of athermoplastic resin capable of sufficiently adhering to thepolyamide-based resin through functional groups and, therefore, thethermoplastic resin (C) and the polyamide-based resin layer (B) arefirmly adhered together.

Accordingly, the thermoplastic polymer layer (A), polyamide-based resinlayer (B) and thermoplastic resin layer (C) in the laminated resinmolding of the invention are firmly adhered together. The phrase “firmlyadhered together” as used herein means that the initial adhesivestrength between the thermoplastic polymer layer (A) and polyamide-basedresin layer (B) and the initial adhesive strength between thepolyamide-based resin layer (B) and thermoplastic resin layer (C) eachshows a value within the range given hereinabove.

The laminated resin molding of the invention is obtained, for example,by the method comprising the thermoplastic polymer layer (A),polyamide-based resin layer (B) and thermoplastic resin layer (C) bysequential extrusion or coextrusion, or by the method comprisingsubjecting the molded layers to contact bonding with heating underpressure. By using such method, it is possible to attain a sufficientlevel of interlaminar adhesive strength between the thermoplasticpolymer layer (A) and polyamide-based resin layer (B) and between thepolyamide-based resin layer (B) and thermoplastic resin layer (C). Thelaminated resin molding can be produced using any of the conventionalthermoplastic resin molding machines, such as injection moldingmachines, compression molding machines, blow molding machines, extrusionmolding machines, etc. Thus, laminated resin moldings in various formssuch as sheet-like or tube-like forms can be obtained. In producing thelaminated resin molding in the form of a multilayer molded article, forexample a multilayer tube, multilayer hose or multilayer tank, such amolding method as multilayer coextrusion molding, multilayer blowmolding or multilayer injection molding can be applied. Among them, thetechnique of extrusion molding, in particular simultaneous multilayercoextrusion molding, is preferably used in molding tubes, hoses andsheets, among others, while the blow molding technique can be suitablyused in molding hollow articles having a cylindrical form, for instance.It is also possible to produce lined materials by laminating the moldedsheet with some other substrate.

As regards the simultaneous multilayer coextrusion molding and blowmolding conditions, the multilayer die temperature is set at such alevel that the thermoplastic polymer will not be deteriorated or willnot foam and that the interlaminar adhesive strength between thepolyamide-based resin layer (B) and thermoplastic resin layer (C) maybecome satisfactory. Broadly, the multilayer die temperature is nothigher than 300° C. and, for accomplishing the first object of theinvention, that temperature is preferably set at 250° C. or below, morepreferably at 230° C. or below, still more preferably at 220° C. orbelow. For achieving the second object of the invention, it ispreferably set at a level exceeding 250° C. but not higher than 300° C.,more preferably at a level not lower than 260° C. but not higher than290° C. The lower limit to the multilayer die temperature is set at thatmelting point of the polyamide-based resin for forming thepolyamide-based resin layer (B) or of the thermoplastic resin forforming the thermoplastic resin layer (C), whichever is lower. As forthe cylinder temperature, a temperature higher by 10 to 50° C. than themelting points of the resins for forming the respective layers isappropriate.

The laminated resin molding may be a laminate comprising thethermoplastic polymer layer (A), polyamide-based resin layer (B) andthermoplastic resin layer (C) alone, or a laminate further comprisingone or more layers other than the thermoplastic polymer layer (A),polyamide-based resin layer (B) and thermoplastic resin layer (C).

The other layer may be a glass fiber layer for reinforcement or a braidlayer made of a polyester or a like resin.

In cases where the thermoplastic polymer layer (A) and thermoplasticresin layer (C) are in contact with the polyamide-based resin layer (B)in the laminated resin molding, the polyamide-based resin layer (B) maycomprise two polyamide-based resin layers, namely a polyamide-basedresin layer (B1) and a polyamide-based resin layer (B2) with at leastone other layers (E) sandwiched between the layers (B1) and (B2). Inthis case, the laminated resin molding is constituted of thethermoplastic polymer layer (A), polyamide-based resin layer (B1), otherlayer (E), polyamide-based resin layer (B2) and thermoplastic resinlayer (C), hence is a laminate resulting from lamination of those fivelayers in that order (hereinafter sometimes referred to as “laminatedresin molding P”).

The resin for forming the other layer (E) can be selected from amongthose thermoplastic polymer species mentioned hereinabove. The cost ofthe laminated resin molding P can be reduced by using a low-pricedgeneral-purpose resin in forming the other layer (E) and thussubstituting that low-priced resin for a part of the polyamide-basedresin which is generally high-priced. Further, by increasing thethickness of the other layer (E), it is possible to make the laminatethick in response to the intended use while suppressing the increase incost. By using a thermoplastic polymer higher in flexibility than thepolyamide-based resin in forming the other layer (E), the flexibility ofthe laminated resin molding P as a whole can be adjusted in response tothe intended use.

The laminate structure of the laminated resin molding P is anappropriate one also in cases where the thermoplastic resin polymerforming the thermoplastic polymer layer (A) and the thermoplastic resinforming the thermoplastic resin layer (C) are similar or the same inkind, in particular when each of them is a resin comprising afluorine-containing ethylenic polymer; no trouble will be encountered inaccomplishing the second object of the invention. In attaining thesecond object of the invention, the thermoplastic resin polymer and thethermoplastic resin layer in the laminated resin molding P arepreferably made of the same resin comprising a fluorine-containingethylenic polymer, more preferably the copolymer (IV) mentionedhereinabove in view of the ease of preparation, among others, while, informing the other layer (E), a relatively low-priced thermoplasticpolymer is preferred and polyethylene or a like polyolefin resin or amodified polyolefin resin is more preferred.

In the practice of the invention, the thermoplastic resin layer (C) maybe further adhered to a layer (D) comprising a fluororesin in the mannerof lamination. If necessary, the fluororesin layer (D) may contain anelectrically conductive material for providing electrical conductivity.In this case, the conductive material is used at an addition levelsufficient to provide electrical conductivity, and the addition levelmay be the same as described hereinabove referring to the thermoplasticresin layer (C).

The fluororesin mentioned above is not particularly restricted but maybe any of those fluororesins capable of being melt molded, including,among others, tetrafluoroethylene/fluoro(alkyl vinyl ether) copolymers[PFAs], tetrafluoroethylene/hexafluoropropylene copolymers [FEPs],ethylene/tetrafluoroethylene copolymers [ETFEs],polychlorotrifluoroethylene [PCTFE], ethylene/chlorotrifluoroethylenecopolymers [ECTFEs]. It may be one of the fluorine-containing ethylenicpolymers mentioned hereinabove.

The laminated resin molding of the invention may further comprise athermoplastic polymer layer (F) as bonded to the thermoplastic polymerlayer (A) in the manner of lamination. In attaining the first object ofthe invention, the thermoplastic polymer forming the thermoplasticpolymer layer (A) and the thermoplastic polymer forming thethermoplastic polymer layer (F) in the laminated resin molding of theinvention each preferably comprises a thermoplastic elastomer, and thethermoplastic polymer is preferably selected so that the thermoplasticpolymer layer (A) and thermoplastic polymer layer (F) may be firmlyadhered to each other. The thermoplastic polymer forming thethermoplastic polymer layer (A) and the thermoplastic polymer formingthe thermoplastic polymer layer (F) may be of the same kind or differentin kind. When the thermoplastic polymer layer (A) and thermoplasticpolymer layer (F) each contains one or more additives or the like, theadditives in both the layers may be of the same kind or different inkind. The thermoplastic polymer forming the thermoplastic polymer layer(F) may be a polymer modified for an improvement in adhesiveness to thepolyamide-based resin. A glass fiber layer or a braid may be sandwichedbetween the thermoplastic polymer layer (A) and thermoplastic polymerlayer (F). In cases where the laminated resin molding of the inventionis used as a fuel tube, for instance, it is desirable that thethermoplastic polymer layer (F) is higher in oil resistance than thethermoplastic polymer layer (A). The thermoplastic polymer layer (F) maybe more flexible than the thermoplastic polymer layer (A).

In achieving the first object of the invention, the polyamide-basedresin layer (B) in the laminated resin molding preferably has athickness not exceeding one fifth of the thickness of the thermoplasticpolymer layer (A). When the thickness exceeds one fifth of the thicknessof the thermoplastic polymer layer (A), the polyamide-based resin layerrelatively low in flexibility becomes relatively thicker and theflexibility of the laminated resin molding obtained will unfavorablydecrease. As for the lower limit to the thickness of the polyamide-basedresin layer (B), a proper level of interlaminar adhesive strength can beattained if the thickness in question does not exceed one fifth of thethickness of the thermoplastic polymer layer (A), even if it is at leastone fortieth of the thickness of the thermoplastic polymer layer (A).

In the case of the laminated resin molding P mentioned above, the totalthickness of the polyamide-based resin layer (B1), polyamide-based resinlayer (B2) and other layer (E) in the laminated resin molding ispreferably not more than one fifth of the thickness of the thermoplasticpolymer layer (A).

In achieving the first object of the invention, the thickness of thethermoplastic resin layer (C) is preferably less than 0.5 mm, althoughit is not particularly restricted. When it is 0.5 mm or thicker, thelaminated resin molding obtained may show decreased transparency in somecases. As regards the lower limit to the thickness of the thermoplasticresin layer (C), that layer can show the desired chemical resistance,barrier quality and bacteria resistance, among others, when thethickness is 0.03 mm or more but does not exceed 0.5 mm.

In attaining the second object of the invention, the total thickness ofthe thermoplastic polymer layer (A) and thermoplastic resin layer (C) inthe laminated resin molding is preferably 1.5 mm or less, morepreferably 1 mm or less. That total thickness is preferably less thanthe thickness of the polyamide resin layer (B). When that totalthickness exceeds the thickness of the polyamide resin layer (B), thestrength of the laminated resin molding in the form of a tube decreasesin some instances.

In accomplishing the first object of the invention, the laminated resinmolding preferably has a modulus of elasticity in tension below 400 MPa,more preferably below 250 MPa. As for the lower limit to the modulus ofelasticity in tension, a level of elasticity sufficient for theapplication as an ordinary tube for industrial use can be attained whenthe modulus of elasticity in tension is within the above range, even ifit is 50 MPa. The tensile modulus of elasticity so referred to herein isthe value measured at room temperature according to ASTM D 638 (1999).The laminated resin molding of the invention preferably has a tensilestrength of 25 MPa or higher.

For use in the field of application where visibility from the outside isrequired, the total luminous transmittance of the laminated resinmolding of the invention is preferably 75% or higher. If it is lowerthan 75%, the laminated resin molding of the invention will beunsatisfactory in transparency when it is to be used as a tube or hose,as described later herein; this is undesirable since the fluid flowingduring use or the presence or absence of deposits on the inside wallcannot be confirmed or checked. As for the upper limit, the totalluminous transmittance may be 97% or lower provided that it is not lowerthan 75%. It is to be adequately selected according to the intended useof the product laminated resin molding, among others. The total luminoustransmittance so referred to herein is the value measured according toJIS K 7105 and, in the case of a tube or hose, the value obtained bycutting out the hose or tube with a cutter or the like, fixing the samein a flattened state and carrying out the measurement.

The laminated resin molding of the invention is a laminate comprisingthe thermoplastic polymer layer (A), polyamide-based resin layer (B) andthermoplastic resin layer (C) and, therefore, it has the excellentflexibility and transparency of the thermoplastic polymer forming thethermoplastic polymer layer (A) and the excellent chemical resistance,heat resistance, weather resistance, electrical insulation properties,nonstickiness, barrier properties, bacteria resistance and otherproperties of the thermoplastic resin forming the thermoplastic resinlayer (C). Further, since the polyamide-based resin forming thepolyamide-based resin layer (B) has an amine value within the specifiedrange, the molding can have good interlaminar adhesive strength evenwhen the thermoplastic polymer forming the thermoplastic polymer layer(A) is a thermoplastic elastomer and coextrusion is carried out at arelatively low temperature so that the thermoplastic elastomer may notproduce bubbles.

In achieving the first object of the invention, the laminated resinmolding can be further improved in flexibility by selecting theabove-mentioned species as the thermoplastic polymer.

Even when immersed in any organic liquid selected from the groupconsisting of methanol, ethanol, fuel C [toluene:xylene=1:1 (byvolume)], CM15 [toluene:xylene:methanol=42.5:42.5:15 (by volume)] andCE10 [toluene:xylene:ethanol=45:45:10 (by volume)] at a temperature of40° C., the laminated resin molding of the invention in which each ofthe thermoplastic polymer layer (A) and thermoplastic resin layer (C) isa fluorine-containing ethylenic polymer layer preferably shows alengthwise elongation in the planar direction and a change in diametereach not exceeding 2%.

The laminated resin molding of the invention in which each of thethermoplastic polymer layer (A) and thermoplastic resin layer (C) is afluorine-containing ethylenic polymer layer preferably shows a fuelpermeation rate not exceeding 1 g/m²/day, more preferably not exceeding0.5 g/m²/day, against any organic liquid selected from the groupconsisting of methanol, ethanol, fuel C [toluene:xylene=1:1 (byvolume)], CM15 [toluene:xylene:methanol=42.5:42.5:15 (by volume)] andCE10 [toluene:xylene:ethanol=45:45:10 (by volume)] at 27° C.

The laminated resin molding of the invention can be molded as a laminateby the simultaneous multilayer coextrusion technique using a coextrusionmachine comprising a die and a plurality of extruders each for feeding aresin to the die. In achieving the first object of the invention, thedie temperature is preferably not higher than 250° C.

Thus, when the die temperature is not higher than 250° C., the method ofproducing laminated resin moldings according to the invention issuitable as a method of producing laminated resin moldings foraccomplishing the first object of the invention, and it consists inproducing laminates by the simultaneous multilayer coextrusion techniqueusing a coextrusion machine comprising a die and a plurality ofextruders each for feeding a resin to the die and is characterized inthat the die temperature is not higher than 250° C.

In accomplishing the second object of the invention, the laminated resinmolding of the invention is preferably molded at a die temperatureexceeding 250° C. but not exceeding 300° C. Thus, the method ofproducing laminated resin moldings according to the invention accordingto which the die temperature is higher than 250° C. but not higher than300° C. is suitable as a method of producing laminated resin moldingsfor accomplishing the second object of the invention.

The die is not particularly restricted but may be any of those dieswhich are generally used in extrusion molding. For example, there may bementioned manifold dies, blow molding dies, ring dies, screw dies, andtubing dies, among others. The die is appropriately selected accordingto the intended use of the product laminated resin moldings. Like in thecase of the multilayer die mentioned above, the die temperature is nothigher than 300° C. In achieving the first object of the invention, itis preferably set at a level not higher than 250° C., more preferablynot higher than 230° C., still more preferably not higher than 220° C.It is set at 250° C. or below, preferably 230° C. or below, morepreferably 220° C. or below. The lower limit to the temperature is setat that melting point of the polyamide-based resin forming thepolyamide-based resin layer (B) or of the thermoplastic resin formingthe thermoplastic resin layer (C), whichever is lower; preferably,however, it is not lower than 170° C., more preferably 190° C. or above.

In achieving the first object of the invention, the thermoplasticpolymer in the laminated resin molding of the invention is preferably athermoplastic elastomer and the thermoplastic resin is preferably afluorine-containing ethylenic polymer so that the molding may haveexcellent flexibility, chemical resistance, liquid chemicalimpermeability and bacteria resistance. In this case, the thermoplasticelastomer is preferably a polyurethane-based elastomer, and thefluorine-containing ethylenic polymer is preferably the copolymer (IV)mentioned hereinabove referring to the fluorine-containing ethylenicpolymer.

In accomplishing the second object of the invention, each of thethermoplastic resin and thermoplastic polymer is preferably afluorine-containing ethylenic polymer so that the laminated resinmolding of the invention may be excellent in chemical resistance,nonstickiness, elution resistance, antifouling quality and bacteriaresistance on both sides and, further, it, as a laminate, may beexcellent in fuel impermeability. Furthermore, the copolymer (IV)mentioned hereinabove referring to the fluorine-containing ethylenicpolymer is preferred as the fluorine-containing ethylenic polymer.

The laminated resin molding of the invention may take the form of amultilayer molded article. The multilayer molded article comprises thelaminated resin molding as at least a part thereof.

As examples of the multilayer molded article, there may be mentioned thefollowing:

Tubes and hoses: tubes or hoses for feeding coatings, liquidchemical-transport tubes or hoses, transport tubes or hoses foragrochemicals, tubes or hoses for drinks, hydraulic tubes or hoses,pneumatic tubes or hoses, tubes to be buried underground in gasstations, automobile fuel piping tubes or hoses, automobile radiatorhoses, brake hoses, air conditioner hoses, electric wires and cables,fuel cell hoses, etc.

Films and sheets: diaphragm pump diaphragms, various packing members andother sliding members required to have high chemical resistance,conveyor belts.Tanks: automobile radiator tanks, liquid chemical bottles, liquidchemical tanks, bags, drug containers, gasoline tanks, etc.Others: carburetor flange gaskets, fuel pump O rings, other variousseals for automobiles, seals in pumps and flow meters for chemicals,other seals for use in chemistry and chemical industries, hydraulicmachine seals, other seals for machinery, gears, etc.

The laminated resin molding of the invention is preferably used in theform of a hose or tube as a multilayer molded article, in particular.

Such laminated resin molding in the form of a hose or tube as amultilayer molded article constitutes an aspect of the invention. Thehose or tube includes the same ones as enumerated hereinabove.

The multilayer molded article mentioned above is preferably a liquidchemical-transport tube or a liquid chemical-transport hose each havingthe thermoplastic polymer layer (A) as the outside layer and thepolyamide-based resin layer (B) as the intermediate layer. Themultilayer molded article in which the thermoplastic resin layer (C)formed out of a thermoplastic resin, in particular a fluorine-containingethylenic polymer, serves as the inside layer is excellent in chemicalresistance and, therefore, can be adequately used as a liquidchemical-transport tube or a liquid chemical-transport hose.

The liquid chemical is not particularly restricted but includes organicor inorganic liquids, for example organic acids such as acetic acid,formic acid, cresols and phenol; inorganic acids such as hydrochloricacid, nitric acid and sulfuric acid; solutions of alkalis such as sodiumhydroxide and potassium hydroxide; alcohols such as methanol andethanol; amines such as ethylenediamine, diethylenetriamine andethanolamines; amides such as dimethylacetamide; esters such as ethylacetate and butyl acetate; fuels such as gasoline, light oil and heavyoil, pseudofuels such as Fuel C, and mixed fuels composed of these and aperoxide, methanol, ethanol and/or the like.

Further, in accomplishing the first object of the invention, themultilayer molded article mentioned above is preferably a tube forfeeding a coating or a hose for feeding a coating each having thethermoplastic polymer layer (A) as the outside layer, the thermoplasticresin layer (C) as the inside layer and the polyamide-based resin layer(B) as the intermediate layer. When the thermoplastic resin layer (C) isformed out of a thermoplastic resin, in particular a fluorine-containingethylenic polymer, the multilayer molded article mentioned above is lowin liquid chemical permeability and excellent in chemical resistanceand, therefore, can be suitably used as a tube for feeding a coating ora hose for feeding a coating, even in transporting an ink diluted withxylene, for instance, without meaning any particular restriction.

Further, in accomplishing the first object of the invention, themultilayer molded article mentioned above is preferably a tube fordrinks or a hose for drinks each having the thermoplastic polymer layer(A) as the outside layer, the thermoplastic resin layer (C) as theinside layer and the polyamide-based resin layer (B) as the intermediatelayer. When the thermoplastic resin layer (C) is formed out of athermoplastic resin, in particular a fluorine-containing ethylenicpolymer, the multilayer molded article mentioned above is resistant tobacteria and is sanitary and, therefore, can be suitably used as a tubefor drinks or a hose for drinks.

Further, in accomplishing the first object of the invention, themultilayer molded article mentioned above is preferably an automobilefuel piping tube or an automobile fuel piping hose each having thethermoplastic polymer layer (A) as the outside layer, the thermoplasticresin layer (C) as the inside layer and the polyamide-based resin layer(B) as the intermediate layer. When the thermoplastic resin layer (C) asthe inside layer is formed out of a thermoplastic resin, in particular afluorine-containing ethylenic polymer, the multilayer molded articlementioned above is low in liquid chemical permeability and, therefore,can be suitably used as an automobile fuel piping tube or an automobilefuel piping hose.

In achieving the first object of the invention, the liquidchemical-transport tube or liquid chemical-transport hose, tube forfeeding a coating or hose for feeding a coating, tube for drinks or hosefor drinks, or automobile fuel piping tube or automobile fuel pipinghose, which is a multilayer molded article, is preferably such that thethermoplastic polymer is a thermoplastic elastomer and the thermoplasticresin is a fluorine-containing ethylenic polymer, since goodflexibility, chemical resistance, liquid chemical impermeability andbacteria resistance can be attained then. In this case, thethermoplastic elastomer is preferably a polyurethane-based elastomer ora polyolefin-based elastomer, and the fluorine-containing ethylenicpolymer is preferably the copolymer (IV) mentioned hereinabove referringto the fluorine-containing ethylenic polymer.

In achieving the second object of the invention, the multilayer moldedarticle is preferably a tube to be buried underground in a gas stationhaving the thermoplastic polymer layer (A) as the outside layer, thethermoplastic resin layer (C) as the inside layer and thepolyamide-based resin layer (B) as the intermediate layer.

When each of the inside layer and outside layer is formed of athermoplastic resin, in particular a fluorine-containing ethylenicpolymer, this multilayer molded article is low in liquid chemicalpermeability and excellent in chemical resistance and elution resistanceand, therefore, is preferably used as an inner tube, in particular, andcan be adequately used even in transporting alcohol-supplemented fuels.When gasoline is transferred from a tank truck to a tank in a gasstation, there arises the possibility of sparking due to electrostaticcharging and, therefore, the thermoplastic resin layer (C) in the innertube inside layer is preferably rendered electrically conductive. Theabove fluorine-containing ethylenic polymer is preferably the copolymer(IV) described hereinabove referring to the fluorine-containingethylenic polymer.

In accomplishing the second object of the invention, the above-mentionedmultilayer molded article, which is low in liquid chemical permeabilityand excellent in chemical resistance, elution resistance and bacteriaresistance, is preferably used also as an outer tube of a duplex tube.Preferably, the multilayer molded article is simultaneously used as theinner tube and outer tube of the duplex tube, although it can also beused either as the inner tube or as the outer tube alone. The tubediameter may be not smaller than 5 mm but not greater than 100 mm.

In accomplishing the second object of the invention, the polyamide resinlayer (B) in the multilayer molded article preferably has theconstitution polyamide/modified polyolefin/polyamide, polyamide/modifiedpolyolefin/polyolefin/modified polyolefin/polyamide orpolyamide/modified polyolefin/Eval/modified polyolefin/polyamide, forinstance. “Eval” is the product derived from an ethylene/vinyl acetatecopolymer by hydrolysis.

In achieving the second object of the invention, the polyamide-basedresin layer (B) in the multilayer molded article is divided into twopolyamide layers, namely the polyamide-based resin layer (B1) andpolyamide-based resin layer (B2) mentioned above, in constituting thelaminate structure of the laminated resin molding P mentioned above, andthese two polyamide-based resin layers may be the same or different inkind. From the ease of preparation viewpoint, however, they arepreferably of the same kind.

In achieving the second object of the invention, the multilayer moldedarticle is preferably a liquid chemical bottle having the thermoplasticpolymer layer (A) as the outside layer, the thermoplastic resin layer(C) as the inside layer and the polyamide-based resin layer (B) as theintermediate layer. When each of the inside layer and outside layer isformed of a thermoplastic resin, in particular a fluorine-containingethylenic polymer, the above-mentioned multilayer molded article is lowin liquid chemical permeability and both the outside and inside surfacesare excellent in chemical resistance and elution resistance and,therefore, that molding is most suitably used as a liquid chemicalbottle. The above fluorine-containing ethylenic polymer is preferablythe copolymer (IV) described hereinabove referring to thefluorine-containing ethylenic polymer.

EFFECTS OF THE INVENTION

The present invention, which has the constitution described hereinabove,can provide laminated resin moldings which are excellent in flexibility,liquid chemical impermeability, chemical resistance, barrier propertiesand bacteria resistance, among others, never undergo changes in sizeafter immersion in fuels and are excellent in interlaminar adhesivestrength. The multilayer molded articles comprising such laminated resinmoldings can be suitably used as tubes or hoses or in like fields ofapplication.

BEST MODES FOR CARRYING OUT THE INVENTION

The following synthesis examples, concrete examples and comparativeexamples illustrate the present invention in further detail. Theseexamples are, however, by no means limitative of the scope of theinvention. Parameter measurements were carried out in the followingmanner.

(1) Amine Value Measurement

One gram of each polyamide-based resin was dissolved in 50 ml ofm-cresol with heating, and the solution was titrated with a 1/10 Naqueous solution of p-toluenesulfonic acid using thymol blue as anindicator to determine the quantity of amino groups occurring in each10⁶ g of the polyamide-based resin.

(2) Acid Value Measurement

One gram of each polyamide-based resin was dissolved in 50 ml of benzylalcohol with heating, and the solution was titrated with a 1/30 N sodiumhydroxide solution in benzyl alcohol using phenolphthalein as anindicator to determine the quantity of carboxyl groups occurring in each10⁶ g of the polyamide-based resin.

(3) Relative Viscosity Measurement

In accordance with JIS K 6810, 1 g of each polyamide-based resin wasdissolved in 100 ml of 98% sulfuric acid, and the measurement wascarried out at 25° C. using an Ubbellohde viscometer.

(4) Measurement of the Number of Carbonate Groups

A film with a thickness of 0.05 to 0.2 mm was prepared by roomtemperature compression molding of a white powder or cut pieces ofpellets obtained by melt extrusion of each of the fluorine-containingethylenic polymers obtained in Synthesis Examples 7 to 14 describedlater herein. In infrared absorption spectroscopic analysis, such a filmshows a peak assignable to the carbonyl group of a carbonate group[—OC(═O)O—] at the absorption wavelength of 1809 cm⁻¹ (ν_(C═O)).Therefore, the absorbance of that ν_(C═O) peak was measured. The number(N) of carbonate groups per 10⁶ main chain carbon atoms was calculatedusing the formula (1) given below.

N=500 AW/εdf  (1)

A: The absorbance of the ν_(C═O) peak in the carbonate group[—OC(═O)O—];ε: The molar extinction coefficient (1.cm⁻¹.mol⁻¹) of the ν_(C═O) peakin the carbonate group [—OC(═O)O—]; based on the data concerning modelcompounds, ε was estimated to be 170;W: The average molecular weight of the monomers as calculated from themonomer composition;d: The density of the film (g/cm³);f: The thickness of the film (mm).

The infrared absorption spectroscopic analysis was carried out by 40times of scanning using a Perkin-Elmer model 1760X FTIR spectrometer(product of Perkin-Elmer). The IR spectrum obtained was subjected toautomatic base line judgment using Perkin-Elmer Spectrum for Ver. 1.4Cfor the measurement of the absorbance of the peak at 1809 cm⁻¹. The filmthickness was measured using a micrometer.

(5) Measurement of the Number of Fluoroformyl Groups

In infrared spectroscopic analysis of a film obtained in the same manneras mentioned above under (4), a peak assignable to the carbonyl group ofa carboxylic acid fluoride group [—C(═O)F] appears at the absorptionwavelength of 1880 cm⁻¹ (ν_(C═O)). Therefore, the absorbance of thatν_(C═O) peak was measured. Using the formula (1) given above, the numberof fluoroformyl groups was determined in the same manner as in themeasurement of the number of carbonate groups as described above under(4) except that the molar extinction coefficient (1.cm⁻¹.mol⁻¹) of theν_(C═O) peak in the carboxylic acid fluoride group was estimated atε=600 based on the data concerning model compounds.

(6) Measurement of the Number of Carboxyl Groups

In infrared spectroscopic analysis of a film obtained in the same manneras mentioned above under (4), a peak assignable to the carbonyl group ofa carboxyl group [—C(═O)OH] appears at the absorption wavelength of 1764cm⁻¹ (ν_(C═O)). Therefore, the absorbance of that ν_(C═O) peak wasmeasured. Using the formula (1) given above, the number of carboxylgroups was determined in the same manner as in the measurement of thenumber of carbonate groups as described above under (4) except that themolar extinction coefficient (1.cm⁻¹.mol⁻¹) of the ν_(C═O) peak in thecarboxyl group was estimated at ε=530 based on the data concerning modelcompounds.

(7) Determination of the Composition of the Fluorine-ContainingEthylenic Polymer

The composition was determined by ¹⁹F-NMR analysis.

(8) Melting Point (Tm) Measurement

A Seiko DSC apparatus was used. The melting peak was recorded whileraising the temperature at a rate of 10° C./minute, and the temperaturecorresponding to the maximum value was regarded as the melting point(Tm).

(9) MFR (Melt Flow Rate) Measurement

Using a melt indexer (product of Toyo Seiki Seisakusho), the weight (g)of the polymer flowing out through a nozzle with a diameter of 2 mm anda length of 8 mm during a unit time (10 minutes) under a load of 5 kg ateach temperature was measured.

(10) Appearances of the Inside and Outside Surfaces of Each MultilayerTube

The tube obtained was cut into half-round halves, and the inside andoutside surfaces of the tube were observed by the eye or under astereoscopic microscope (×50). The following criteria were used injudging the surfaces with respect to such bad conditions as surfaceroughness, bubble formation and so forth.

◯: No bad condition in appearance is seen at all.Δ: Some or other bad conditions are found on less than 2% of the wholesurface.X: Some or other bad conditions are found on 2% or more of the wholesurface.

(11) Measurement of the Initial Adhesive Strength of the Multilayer Tube

Test specimens with a length of 5 cm and a width of 1 cm were cut out ofeach tube and subjected to an adhesion test (peeling at 180°) using aTensilon universal testing machine at a rate of 25 mm/minute. Theinterlaminar initial adhesive strength was determined as the mean offive maxima in elongation-tensile strength graphs.

(12) Total Luminous Transmittance

A 3-cm-long piece was cut off from each tube and cut open lengthwise ata site. The opened piece was fixed on a supporting member, and the totalluminous transmittance was measured using a haze meter (product of ToyoSeiki Seisakusho).

(13) Modulus of Elasticity in Tension and Tensile Strength

The values (MPa) reported herein are those measured at room temperatureaccording to ASTM D 638 (1999) (rate of pulling: 50 cm/min).

(14) Measurement of Changes in Size after Immersion in a Fuel

A 30-cm-long section was cut off from each tube, and CM15[toluene:xylene:methanol=42.5:42.5:15 (by volume)] was sealed in thetube section-using Swagelok fittings (available from Osaka ValveFittings). Further, this tube was immersed in a CM15 bath maintained ata constant temperature (40° C.) for 1000 hours. Size measurements werecarried out before and after immersion and the percent change wascalculated as follows: (change in size/original size)×100. Each measuredvalue was expressed in terms of absolute value.

(15) Fuel Permeation Rate

A 200-cm-long section of the tube was cut off, and the liquid chemical(CM15) was sealed in the tube section. Further, this tube section wasplaced in a thermostat maintained at a constant temperature (27° C.) andweighed. The rate was calculated from the time point of arrival at aconstant rate of weight loss per unit time. The inside surface area ofthe tube section was used as the area for calculation.

SYNTHESIS EXAMPLE 1 Synthesis of Polyamide-Based Resin PA-A (nylon 12)

An autoclave was charged with 20 kg of ω-laurolactam and 1 kg ofdistilled water and, after nitrogen substitution, the temperature wasraised to 280° C. Then, the system inside was maintained at 3.2 MPa atthe same temperature for 5 hours, followed by gradual pressure release.During the pressure release period until returning of the system toatmospheric pressure, the w-laurolactam was allowed to be dissolved inwater and, after dissolution, the solution was stirred. After returningof the system to atmospheric pressure, 100 g of stearic acid was addedand the resulting mixture was further stirred at 260° C. in a nitrogenatmosphere for 5 hours. The contents were then discharged, cooled withwater and submitted to a pelletizer to give white pellets(polyamide-based resin PA-A). Analyses revealed that these pellets had amelting point of 178° C., an acid value of 28 (equivalents/10⁶ g), anamine value of 6.8 (equivalents/10⁶ g), and a relative viscosity of 3.0.

SYNTHESIS EXAMPLE 2 Synthesis of Polyamide-Based Resin PA-B (Nylon 12)

Polyamide-based resin PA-B was obtained in the same manner as inSynthesis Example 1 except that the addition of stearic acid was omittedand that the time of stirring in a nitrogen atmosphere was 4 hours. Theresults of analyses are shown in Table 1.

SYNTHESIS EXAMPLE 3 Synthesis of Polyamide-Based Resin PA-C (Nylon 11)

An autoclave was charged with 20 kg of 11-aminoundecanoic acid in powderform, 5 kg of distilled water and 100 g of a 30% aqueous solution ofphosphoric acid and, after nitrogen substitution, tightly closed. Thetemperature was raised to and maintained at 120° C. for 2 hours and thenfurther raised to 220° C., and the system inside was maintained at thattemperature and a pressure of 0.4 MPa for 2 hours, followed by gradualpressure release. During the pressure release period until returning ofthe system to atmospheric pressure, the 11-aminoundecanoic acid wasallowed to be dissolved in water and, after dissolution, the solutionwas stirred. After returning of the system to atmospheric pressure, 110g of stearic acid was added and the resulting mixture was furtherstirred at 265° C. in a nitrogen atmosphere for 4 hours. The contentswere then discharged, cooled with water and submitted to a pelletizer togive white pellets (polyamide-based resin PA-C). The results of analysesare shown in Table 1.

SYNTHESIS EXAMPLE 4 Synthesis of Polyamide-Based Resin PA-D (Nylon 11)

Pellets (polyamide-based resin PA-D) were obtained in the same manner asin Synthesis Example 3 except that the addition of stearic acid wasomitted and that the time of stirring in a nitrogen atmosphere was 3hours. The results of analyses are shown in Table 1.

SYNTHESIS EXAMPLE 5 Synthesis of Polyamide-Based Resin PA-E(Plasticizer-Containing Nylon 12)

The polyamide-based resin PA-B obtained in Synthesis Example 2 andN-ethyltoluenesulfonamide were dry-blended together in a weight ratio of95/5, and the resulting mixture was extruded at 260° C. and a dischargerate of 350 g/minute using a twin-screw extruder (Ikegai Corporationmodel PCM-45) and, after water cooling, the extrudate was submitted to apelletizer to give white pellets (polyamide-based resin PA-E). Theresults of analyses are shown in Table 1.

SYNTHESIS EXAMPLE 6 Synthesis of Polyamide-Based Resin PA-F (Nylon 6)

An autoclave was charged with 20 kg of ε-caprolactam and 2 kg ofdistilled water and, after nitrogen substitution, the temperature wasraised to 120° C. While maintaining that temperature, the ε-caprolactamwas allowed to be dissolved in water and, after dissolution, stirringwas started. The temperature was further raised to 220° C., and thesystem inside was maintained at that temperature and at a pressure of0.4 MPa for 5 hours. The temperature was then raised to 250° C. withgradual pressure release.

After returning of the system to atmospheric pressure, the contents werefurther stirred at 250° C. in a nitrogen atmosphere for 3 hours, thendischarged, cooled with water and submitted to a pelletizer to givewhite pellets. These pellets were then immersed in distilled water at80° C. for 12 hours for extraction of low-molecular-weight substancessuch as the monomer. The pellets were thoroughly dried and subjected tothe subsequent procedure. The results of analyses of the pellets(polyamide-based resin PA-F) after drying are shown in Table 1.

TABLE 1 Melting Synthesis Amine value Acid value point Relative ExamplePolyamide-based resin (equivalents/10⁶ g) (equivalents/10⁶ g) (° C.)viscosity 1 PA-A Nylon 12 6.8 28 178 3.0 2 PA-B Nylon 12 24 29 178 3.2 3PA-C Nylon 11 8.4 33 186 2.9 4 PA-D Nylon 11 32 34 186 2.9 5 PA-E Nylon12 + plasticizer 23 28 174 3.0 6 PA-F Nylon 6 31 35 224 3.4

SYNTHESIS EXAMPLE 7 Synthesis of Fluorine-Containing Ethylenic PolymerF-A

An autoclave was charged with 380 L of distilled water and, afterthorough nitrogen substitution, further charged with 75 kg of1-fluoro-1,1-dichloroethane, 155 kg of hexafluoropropylene and 0.5 kg ofperfluoro(1,1,5-trihydro-1-pentene). The system inside was maintained at35° C. and at a rate of stirring of 200 rpm. Then, tetrafluoroethylenewas fed under pressure until arrival at 0.7 MPa, ethylene was then fedunder pressure until arrival at 1.0 MPa and, thereafter, 2.4 kg ofdi-n-propyl peroxydicarbonate was charged into the autoclave to initiatethe polymerization. To compensate the system inside pressure dropresulting from the progress of the polymerization, a mixed gas composedof tetrafluoroethylene/ethylene/hexafluoropropylene 40.5/44.5/15.0 (inmole percent) was continuously fed to thereby maintain the system insidepressure at 1.0 MPa. And, a total amount of 1.5 kg ofperfluoro(1,1,5-trihydro-1-pentene) was continuously fed, and stirringwas continued for 20 hours. After pressure release to atmosphericpressure, the reaction product was washed with water and dried to give205 kg of a powder (fluorine-containing ethylenic polymer F-A). Theresults of analyses of the powder obtained are shown in Table 2.

SYNTHESIS EXAMPLES 8 AND 9 Synthesis of Fluorine-Containing EthylenicPolymers F-B and F-C

Fluorine-containing ethylenic polymers F-B and F-C were obtained in thesame manner as in Synthesis Example 7 according to the respectivemonomer compositions shown in Table 2. The results of analyses of thepolymers obtained are shown in Table 2.

SYNTHESIS EXAMPLE 10 Fluorine-Containing Ethylenic Polymer F-D

An autoclave was charged with 400 L of distilled water and, afterthorough nitrogen substitution, further charged with 320 kg ofperfluorocyclobutane, 80 kg of hexafluoropropylene, 19 kg oftetrafluoroethylene and 6 kg of vinylidene fluoride. The system insidewas maintained at 35° C. and at a rate of stirring of 180 rpm. Then, 5kg of di-n-propyl peroxydicarbonate was fed to initiate thepolymerization. To compensate the system inside pressure drop resultingfrom the progress of the polymerization, a mixed gas composed oftetrafluoroethylene/vinylidene fluoride/hexafluoropropylene=50/40/10 (inmole percent) was continuously fed to thereby maintain the system insidepressure at a constant level. After 30 hours of continuous stirring andthe subsequent pressure release to atmospheric pressure, the reactionproduct was washed with water and dried to give 195 kg of a powder(fluorine-containing ethylenic polymer F-D). The results of analyses ofthe powder obtained are shown in Table 2.

SYNTHESIS EXAMPLE 11 Synthesis of Fluorine-Containing Ethylenic PolymerF-E

An autoclave was charged with 400 L of distilled water and, afterthorough nitrogen substitution, further charged with 75 kg of1-fluoro-1,1-dichloroethane, 190 kg of hexafluoropropylene and 1.5 kg ofperfluoro(1,1,5-trihydro-1-pentene). The system inside was maintained at35° C. and at a rate of stirring of 200 rpm. Then, tetrafluoroethylenewas fed under pressure until arrival at 0.7 MPa, ethylene was then fedunder pressure until arrival at 10 kg/cm² and, thereafter, 2.6 kg ofdi-n-propyl peroxydicarbonate was charged into the autoclave to initiatethe polymerization. To compensate the system inside pressure dropresulting from the progress of the polymerization, a mixed gas composedof tetrafluoroethylene/ethylene/hexafluoropropylene=40.5/42.5/17.0 (inmole percent) was continuously fed to thereby maintain the system insidepressure at 1.0 MPa. After 30 hours of continuous stirring and thesubsequent pressure release to atmospheric pressure, the reactionproduct was washed with water and dried to give 178 kg of a powder. Thepowder obtained was then submitted to a single-screw extruder (TanabePlastic Kikai model VS50-24). Extrusion at a cylinder temperature of320° C. gave pellets (fluorine-containing ethylenic polymer F-E). Theresults of analyses of the pellets obtained are shown in Table 2.

SYNTHESIS EXAMPLE 12 Synthesis of Fluorine-Containing Ethylenic PolymerF-F

An autoclave was charged with 25 kg of distilled water and, afterthorough nitrogen substitution, further charged with 50 kg ofperfluorocyclobutane and 10 kg of perfluoro(methyl vinyl ether), and thesystem inside was maintained at 35° C. and at a rate of stirring of 215rpm. Then, tetrafluoroethylene was fed under pressure until arrival at0.78 MPa and, then, 150 kg of di-n-propyl peroxydicarbonate was fed toinitiate the polymerization.

To compensate the system inside pressure drop resulting from theprogress of the polymerization, a mixed gas composed ofperfluorocyclobutane/tetrafluoroethylene/perfluoro(methyl vinylether)=10/76.6/13.4 (in mole percent) was continuously fed to therebymaintain the system inside pressure at 0.78 MPa. After 30 hours ofcontinuous stirring and the subsequent pressure release to atmosphericpressure, the reaction product was washed with water and dried to give30 kg of a powder (fluorine-containing ethylenic polymer F-F). Theresults of analyses of the powder obtained are shown in Table 2.

SYNTHESIS EXAMPLE 13 Synthesis of Fluorine-Containing Ethylenic PolymerF-G

An autoclave was charged with 9.5 kg of the fluorine-containingethylenic polymer F-B obtained in Synthesis Example 8, 700 g of 28%aqueous ammonia and 10 L of distilled water, the system was heated withstirring, and stirring was continued at 80° C. for 7 hours. The contentswere washed with water and dried to give 9.5 kg of a powder. Suchtreatment converted the active functional groups (carbonate andfluoroformyl groups) of the polymer to amide groups low in reactivity.Infrared spectroscopic analysis confirmed that this conversion to amidegroups was quantitative. The results of analyses of the polymer afterthe above treatment are shown in Table 2.

SYNTHESIS EXAMPLE 14 Synthesis of Fluorine-Containing Ethylenic PolymerF-H

The fluorine-containing ethylenic polymer F-B obtained in SynthesisExample 8 and acetylene black were mixed up in a Henschel mixer in aweight ratio of 86:14, followed by melt kneading at 245° C. on a 40(twin-screw extruder (for convenience sake, the acetyleneblack-containing mixture obtained is referred to as “fluorine-containingpolymer F-H”). The results of analyses thereof are shown in Table 2.

In Table 2, TFE stands for tetrafluoroethylene, Et for ethylene, HFP forhexafluoropropylene, VdF for vinylidene fluoride, PMVE forperfluoro(methyl vinyl ether), and HF-Pe forperfluoro(1,1,5-trihydro-1-pentene).

TABLE 2 Carbonyl group contents (groups/1 × 10⁶ Total main chainluminous Fluororesin carbon atoms) transmittance Melting MFR SynthesisMonomer composition (mole %) Carbonate Fluoroformyl of 500-μm- point(g/10 min) Example Designation TFE Et HFP VdF PMVE HF-Pe group groupthick film (° C.) 265° C. 7 F-A 40.8 44.8 13.9 — — 0.5 300 3 92 162.5 508 F-B 46.2 43.8 9.5 — — 0.5 255 5 91 194.3 25 9 F-C 47.1 44.1 8.3 — — —189 7 90 207.4 18 10 F-D 51.3 — 9.8 38.9 — 0.5 311 3 92 169.2 40 11 F-E40.5 45.0 14.0 — — 0.5 67 67 91 170.2 24 12 F-F 84.5 — — — 15.5 — 330 390 210.0 20 13 F-G 46.1 43.8 9.6 — — 0.5 Not detected Not detected 91193.5 20 14 F-H 46.1 43.8 9.6 — — 0.5 75 37 — 196.1 4

EXPERIMENT EXAMPLE 1

Using a three-resin three-layer coextruding machine equipped with amultimanifold die, a tube with an outside diameter of 8 mm and an insidediameter of 6 mm the outer layer of which was formed of a thermoplasticelastomer, the intermediate layer of which was formed of apolyamide-based resin and the inner layer of which was formed of afluorine-containing ethylenic polymer was continuously molded by feedingthe thermoplastic elastomer, polyamide-based resin andfluorine-containing ethylenic polymer specified in Table 3 to theextruders for the outer, intermediate and inner layers, respectively.The molding conditions and the results of evaluation of the tubeobtained are shown in Table 3.

EXPERIMENT EXAMPLES 2 TO 20

Tubes were molded in the same manner as in Experiment Example 1 exceptthat the resins and molding conditions used in Experiment Examples 2 to11 were as shown in Table 3 and those used in Experiment Examples 12 to20 were as shown in Table 4. The molding conditions used and the resultsof evaluation of the tubes obtained in Experiment Examples 2 to 11 areshown in Table 3 and those in Experiment Examples 12 to 20 are shown inTable 4.

In Tables 3 and 4, the thermoplastic elastomer TPU-1 stands for 2288(polyurethane-based elastomer produced by using a polyether polyol as along-chain diol; product of Dainichiseika Color & Chemicals Mfg. Co.),TPU-2 for 1078 (polyurethane-based elastomer produced by using apolyester polyol as a long-chain diol; product of Dainichiseika Color &Chemicals), and TPU-3 for 890 (polyurethane-based elastomer produced byusing a polycarbonate polyol as a long-chain diol; product ofDainichiseika Color & Chemicals).

TABLE 3 Experiment Example 1 2 3 4 5 6 Outer layer thermoplastic polymerTPU1 TPU1 TPU1 TPU1 TPU1 TPU1 Intermediate layer resin PA-E PA-E PA-EPA-E PA-E PA-E Inner layer resin F-A F-B F-C F-D F-E F-F Cylinder Outerlayer 210 210 210 210 210 210 temperature Intermediate layer 210 210 210210 210 210 (° C.) Inner layer 210 220 230 220 220 220 Die temperature(° C.) 220 230 235 230 230 230 Tube takeoff speed (m/min) 6 6 6 6 6 6Each layer Outer layer 1 1 1 1 1 1 thickness Intermediate layer 0.050.05 0.05 0.05 0.05 0.05 (mm) Inner layer 0.25 0.25 0.25 0.25 0.25 0.25Total luminous transmittance (%) 79 80 81 80 81 80 Modulus of elasticity175 170 170 165 175 165 in tension (MPa) Appearance of tube inside ◯ ◯ ◯◯ ◯ ◯ and outside surfaces Adhesive Outer layer/ No peeling No peelingNo peeling No peeling No peeling No peeling strength intermediate layeroff off off off off off (N/cm) Intermediate layer/ 45 47 47 43 45 35inner layer Experiment Example 7 8 9 10 11 Outer layer thermoplasticpolymer TPU1 TPU1 TPU1 TPU2 TPU3 Intermediate layer resin PA-D PA-B PA-FPA-E PA-E Inner layer resin F-B F-B F-B F-B F-B Cylinder Outer layer 210210 240 210 210 temperature Intermediate layer 210 210 240 210 210 (°C.) Inner layer 220 220 220 220 220 Die temperature (° C.) 230 230 240230 230 Tube takeoff speed (m/min) 6 6 10 6 6 Each layer Outer layer 1 11 1 1 thickness Intermediate layer 0.05 0.05 0.05 0.05 0.05 (mm) Innerlayer 0.25 0.25 0.25 0.25 0.25 Total luminous transmittance (%) 81 80 7880 79 Modulus of elasticity 170 170 170 165 170 in tension (MPa)Appearance of tube inside and ◯ ◯ ◯ ◯ ◯ outside surfaces Adhesive Outerlayer/ No peeling No peeling No peeling No peeling No peeling strengthintermediate layer off off off off off (N/cm) Intermediate layer/ 46 4749 47 47 inner layer

TABLE 4 Experiment Example 12 13 14 15 16 17 18 19 20 Outer layerthermoplastic polymer TPU-1 TPU-1 TPU-2 TPU-2 TPU-1 TPU-1 TPU-1 TPU-2 —Intermediate layer resin PA-C PA-C PA-A PA-A PA-B PA-B — — PA-E Innerlayer resin F-B F-B F-A F-A F-G F-G F-B F-A F-G Cylinder Outer layer 210210 210 210 210 210 210 210 210 temperature Intermediate layer 245 210245 210 245 210 — — 210 (° C.) Inner layer 260 210 260 210 260 210 210210 210 Die temperature (° C.) 260 220 260 220 260 220 240 220 260 Tubetakeoff speed (m/min) 6 6 6 6 6 6 6 6 6 Each layer Outer layer 1 1 1 1 11 1 1 — thickness Intermediate layer 0.05 0.05 0.05 0.05 0.05 0.05 0.050.05 1.05 (mm) Inner layer 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25Total luminous transmittance (%) 40 80 40 79 42 53 82 82 67 Modulus ofelasticity — — — — — — — — 900 in tension (MPa) Appearance of tubeinside and Failure in ◯ Failure in ◯ Failure in ◯ ◯ ◯ ◯ outside surfacesmoldingx moldingx moldingx Adhesive Outer layer/ — No peeling — Nopeeling — No peeling 5 5 45 strength intermediate layer off off off(N/cm) Intermediate layer/ — 8 — 7 — 6 inner layer

As is evident from the results shown in Table 3 and Table 4, the tubesof Experiment Examples 1 to 11 were all satisfactory in tube inside andoutside surface appearance and in initial interlaminar adhesivestrengths. Even when the intermediate layer-forming polyamide-basedresin was a plasticizer-containing one, the appearance and initialadhesive strengths were good. On the contrary, the tubes of ExperimentExample 13 and Experiment Example 15, in which the polyamide-basedresins used were low in amine value, and the tubes of Experiment Example12 and Experiment Example 14, in which the polyamide-based resins usedwere low in amine value and the die temperature in molding was above250° C., were inferior either in initial intermediate layer/inner layeradhesive strength or in tube inside and outside surface appearance.

The tubes of Experiment Examples 16 and 17, in which thefluorine-containing ethylenic polymer used was an amide group-containingone resulting from carbonyl group-containing group-to-amide groupconversion, were inferior in initial intermediate layer/inner layeradhesive strengths and in tube inside and outside surface appearance,irrespective of the die temperature in tube molding.

When no polyamide intermediate layer was employed, even the carbonylgroup-containing, fluorine-containing ethylenic polymers failed toprovide good adhesion, as shown by the results of Experiment Examples 18and 19.

As shown by the result of Experiment Example 20, the two-layer tube witha polyamide as the outer layer was inferior in total luminoustransmittance.

EXPERIMENT EXAMPLES 21 TO 24

Using a three-resin three-layer coextruding machine equipped with amultimanifold die, tubes the outer layer of which was formed of athermoplastic elastomer, the intermediate layer of which was formed of apolyamide-based resin and the inner layer of which was formed of afluorine-containing ethylenic polymer were continuously molded byfeeding the thermoplastic elastomer, polyamide-based resin andfluorine-containing ethylenic polymer respectively specified in Table 5to the extruders for the outer, intermediate and inner layers,respectively. The molding conditions and the results of evaluation ofthe tubes obtained are shown in Table 5.

In Table 5, the thermoplastic elastomer OP-1 stands for thepolyolefin-based elastomer Santoprene 191-70PA (product of AES JapanLtd.).

TABLE 5 Experiment Example 21 22 23 24 Outer layer thermoplastic polymerOP1 OP1 OP1 OP1 Intermediate layer resin PA-E PA-E PA-A PA-E Inner layerresin F-B F-H F-B F-B Cylinder Outer layer 210 210 210 210 temperatureIntermediate layer 245 245 245 245 (° C.) Inner layer 250 260 250 250Die temperature (° C.) 235 245 235 270 Tube takeoff speed (m/min) 2 2 22 Each layer Outer layer 0.2 0.2 0.2 0.2 thickness Intermediate layer0.15 0.15 0.15 0.15 (mm) Inner layer 0.8 0.8 0.8 0.8 Tube diameter (mm)15 15 15 — Appearance of tube inside and ◯ ◯ ◯ Failure in outsidesurfaces moldingx Modulus of elasticity in tension 150 170 200 Notmeasured (MPa) Tube resistance value (MΩ/sq) — 0.2 — — Adhesive Outerlayer/ No peeling No peeling No peeling — strength intermediate layeroff off off (N/cm) Intermediate layer/ No peeling No peeling 10 — innerlayer off off

As is evident from the results shown in Table 5, the tubes of ExperimentExamples 21 and 22, in which the inner layer was formed of afluorine-containing ethylenic polymer derived from TFE/Et/HFP/HF-Pe andthe lamination was carried out at a die temperature lower than 250° C.,were satisfactory in tube inside and outside surface appearance and ininitial interlaminar adhesive strengths. The tube of Experiment Example23, in which the polyamide-based resin used was low in amine value, wasinferior in initial intermediate layer/inner layer adhesive strength. InExperiment Example 24, in which the die temperature was above 250° C.,no tube could be molded.

EXPERIMENT EXAMPLES 25 TO 30

Using a three-resin three-layer coextruding machine equipped with amultimanifold die, tubes the outer layer of which was formed of athermoplastic polymer, the intermediate layer of which was formed of apolyamide-based resin and the inner layer of which was formed of afluorine-containing ethylenic polymer were continuously molded byfeeding the fluorine-containing ethylenic polymer, polyamide-based resinand fluorine-containing ethylenic polymer respectively specified inTable 6 to the extruders for the outer, intermediate and inner layers,respectively. The molding conditions and the results of evaluation ofthe tubes obtained are shown in Table 6.

TABLE 6 Experiment Example 25 26 27 28 29 30 Outer layer thermoplasticpolymer F-B F-B F-B F-F F-B — Intermediate layer resin PA-E PA-E PA-EPA-E PA-A PA-E Inner layer resin F-B F-H F-F F-F F-B F-B Cylinder Outerlayer 250 250 250 250 250 — temperature Intermediate layer 245 245 245245 245 245 (° C.) Inner layer 250 260 250 250 250 250 Die temperature(° C.) 270 280 270 270 270 270 Tube takeoff speed (m/min) 4 4 4 4 4 4Each layer Outer layer 0.25 0.25 0.25 0.25 0.25 — thickness Intermediatelayer 0.65 0.65 0.65 0.65 0.65 0.9 (mm) Inner layer 0.25 0.25 0.25 0.250.25 0.25 Tube diameter (mm) 8.2 8.2 8.2 8.2 8.2 8.2 Appearance of tubeinside and ◯ ◯ ◯ ◯ ◯ ◯ outside surfaces Change in size Diameter <2% <2%<2% <2% <2% >2% after immersion Length <2% <2% <2% <2% <2% >2% in fuel(%) Fuel permeation CM15, 27° C. 0.3 0.3 0.2 0.1 0.3 0.6 rate (g/m²/day)Tube resistance value (MΩ/sq) — 0.1 — — — — Adhesive Outer layer/ 46 4547 No peeling 15 — strength intermediate layer off (N/cm) Intermediatelayer/ 45 No peeling No peeling No peeling 15 45 inner layer off off off

As is evident from the results shown in Table 6, the tubes of ExperimentExamples 25 to 28 (in particular the tube of Experiment Example 28), inwhich one or two fluorine-containing ethylenic polymers were used informing the outer and inner layers, were satisfactory in tube inside andoutside surface appearance and in initial interlaminar adhesivestrengths. Even when the intermediate layer-forming polyamide-basedresin was a plasticizer-containing one, the appearance and initialadhesive strength were good. Further, the fuel permeation rates were aslow as 0.5 g/m²/day or lower, and the changes in size after immersion infuel were not greater than 2%.

On the contrary, the tube of Experiment Example 29, in which thepolyamide-based resin used was low in amine value, was inferior ininitial intermediate layer/inner layer adhesive strength and in initialintermediate layer/outer layer adhesive strength.

Furthermore, in Experiment Example 30, in which no fluorine-containingethylenic polymer outer layer was formed, the fuel impermeability wasunsatisfactory and the change in size after immersion in fuel exceeded2%.

INDUSTRIAL APPLICABILITY

The invention, which has the constitution described hereinabove, canprovide laminated resin moldings which are excellent in flexibility,liquid chemical impermeability, chemical resistance, barrier quality andbacteria resistance, among others, will not show changes in size afterimmersion in fuels and are excellent in interlaminar adhesive strength.The multilayer molded articles obtainable based on the above-mentionedlaminated resin moldings can be suitably used as tubes or hoses or inother fields of application.

1-15. (canceled)
 16. A laminated resin molding comprising athermoplastic polymer layer (A), a polyamide-based resin layer (B) and athermoplastic resin layer (C), wherein said thermoplastic polymer layer(A), said polyamide-based resin layer (B) and said thermoplastic resinlayer (C) are laminated in that order and firmly adhered to one another,said thermoplastic polymer is to adhere to the polyamide-based resin bythermal fusion bonding and comprises a fluorine-containing ethylenicpolymer, said polyamide-based resin has an amine value of 10 to 60(equivalents/10 g), said thermoplastic resin contains a functionalgroup, is to thereby firmly adhere to said polyamide-based resin bythermal fusion bonding and comprises a fluorine-containing ethylenicpolymer, said functional group contains carbonyl group.
 17. Thelaminated resin molding according to claim 16 wherein thefluorine-containing ethylenic polymer is (II) copolymers obtained bypolymerizing at least tetrafluoroethylene and a compound represented bythe general formula (ii):CF₂═CF—Rf¹  (ii) wherein Rf¹ represents CF₃ or ORf² and Rf² represents aperfluoroalkyl group containing 1 to 5 carbon atoms or (IV) copolymersderived from at least the following a, b and c: a. 20 to 89 mole percentof tetrafluoroethylene, b. 10 to 79 mole percent of ethylene, and c. 1to 70 mole percent of a compound represented by the general formula(ii):CF₂═CF—Rf¹  (ii) wherein Rf¹ represents CF₃ or ORf² and Rf² represents aperfluoroalkyl group containing 1 to 5 carbon atoms.
 18. The laminatedresin molding according to claim 16, wherein the polyamide-based resinhas an acid value of not higher than 80 equivalents/10⁶ g.
 19. A methodfor producing the laminated resin molding according to claim 16, whichcomprises laminating by the simultaneous multilayer coextrusiontechnique using a coextruding machine comprising a die and a pluralityof extruders each for feeding a resin to said die, said die temperaturebeing higher than 250° C. and not higher than 300° C.
 20. A multilayermolded article comprising the laminated resin molding according to claim16.
 21. The multilayer molded article according to claim 20 which is ahose or a tube.
 22. The multilayer molded article according to claim 20which is a tube to be buried underground in a gas station.
 23. Themultilayer molded article according to claim 20 which is an inner tubeor an outer tube of a duplex tube.